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Scientific American Supplement, No. 664, September 22,1888
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SCIENTIFIC AMERICAN SUPPLEMENT NO. 664



NEW YORK, SEPTEMBER 22, 1888

Scientific American Supplement. Vol. XXVI., No. 664.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

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TABLE OF CONTENTS.

PAGE I. ARCHITECTURE.—The Commercial Exchange, Paris.—History of the new building, with its general design and architectural features.—2 illustrations 10607

The New Central Railway Station at Frankfort-on-the-Main.—A full description of this gigantic structure, with its constructive features and cost.—2 illustrations 10605

II. ART OF WAR.—Gun Practice in the French Navy.—Gun practice at sea against a moving target.—1 illustration 10599

Modern Cavalry on the Field of Battle.—By Col. R. S. LIDDELL.—An exhaustive paper on this subject, treating of a much discussed branch of military tactics 10600

III. BIOLOGY.—Subterraneous Flora and Fauna.—By Dr. Otto Zacharias.—A popular article on the interesting subject of animal and vegetable life underground.—8 illustrations 10612

IV. CHEMISTRY.—Pepsin.—By A. PERCY SMITH, F.I.C., F.C.S.—The analysis of pepsin, difficulties of the usual method, and simple comparative test, applicable by any one 10611

V. CIVIL ENGINEERING.—Timber and Some of Its Diseases.—By H. MARSHALL WARD.—Continuation of this valuable series, treating of fungus life and its destructive effects.—5 illustrations 10613

VI. ELECTRICITY.—A Basis from which to Calculate Charges for Electric Motor Service.—A practical paper treating of the percentage of horse power hours used in different industries 10608

VII. ETHNOLOGY.—A Chinese Imperial Cemetery.—The cemetery of the emperors of the Ming dynasty.—The remarkable statues and buildings.—2 illustrations 10610

How a Mound was Built.—An interesting contribution to the history of the Ohio mounds by Mr. GERARD FOWKE 10609

Some Abyssinian Customs.—The hair dressing of the Abyssinian women.—Their method of grinding pepper.—3 illustrations 10609

VIII. MEDICINE AND SURGERY.—A New Surgical Operation.—Dr. Brudenell Carter's operation for relieving pressure on the optic nerve 10611

Dyspepsia, its causes and prevention.—How this malady is caused and how easily it may be guarded against, an essay in prophylaxis 10610

IX. MECHANICAL ENGINEERING.—Coal Tar as Fuel for Steam Boilers.—By JOHN McCRAE, of Dundee.—A review of the economy of tar firing and of the method employed by the writer.—1 illustration 10604

Steam Generator of Serpollet Brothers, producing steam instantaneously.—A new inexplodible steam generator, its construction and application to a tricycle.—3 illustrations 10602

Transmission of Power between Bodies Moving at Different Velocities.—A simple system of transmitting power applicable in many places 10602

X. MISCELLANEOUS.—Note on Missouri Marble 10614

Water Blast Pump.—A filter pump of simplified and improved construction.—3 illustrations 10602

XI. NAVAL ENGINEERING.—Iron Sailing Ships.—Scotch sailing ships, built of iron and steel, the favorite sizes and rigging adopted.—1 illustration 10602

XII. SANITARY ENGINEERING.—Putzeys' Flushing Reservoir.—A French invention, applicable in sewage disposal and pipe flushing.—1 illustration 10611

XIII. TECHNOLOGY.—Gas Lighting by High Power Burners.—A review of a number of regenerative and other gas burners and their practical success 10603

Synchronizing Clocks.—A simple synchronizing mechanism described and illustrated.—1 illustration 10604

Watch Cleaning and Repairing.—A long paper treating of the details of watch cleaning from the practical standpoint 10604

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GUN PRACTICE IN THE FRENCH NAVY.

The gunners of the French fleet are possessed of a skill which is recognized by all the maritime powers, and these picked men proved this at the siege of Paris, where they made themselves illustrious, not only by their courage and their coolness, but also by the accuracy of their firing.

Nothing is neglected, moreover, to keep up the precision of hand and eye that distinguishes them, and which has become so much the more necessary in that it is no longer a question of firing a broadside at the enemy and reckoning on one ball being more fortunate than another in damaging the enemy's ship. At present, the most powerful ironclad has four, and sometimes six or eight, guns of large caliber, which are of from 30 to 100 tons. Every shot represents not only an enormous sum, but also a prodigious force expended, and so powder must not be used too lavishly, since the shot should be in relation with the colossal power that it represents, and the shell adopted in the navy is accompanied with so disastrous effects that a single one, well directed, is capable of reducing the enemy's ship to impotence. So exercises in firing are becoming more and more frequent, and they have a right to be multiplied, inasmuch as the present guns are complicated affairs, the maneuvering of which requires constant practice.

Our engraving represents one of these exercises performed by the Squadron of the North, which is of recent organization, and which consists of the three ironclads Marengo, Suffren, and Ocean, and three coast guards Furieux, Fulminant, and Tonnerre. Each of the ironclads is provided with four 27 cm. guns and four 24 cm. ones, not counting the revolving guns, which constitute the small artillery reserved for fighting torpedo boats. The Furieux has two 34 cm. guns, and the Tonnerre and Fulminant each two 37 cm. ones.

An endeavor is made, as far as possible, to practice firing such as is done in a naval action, that is, at moving targets. To this effect, the dispatch boat Epervier tows a rectangular float about two meters in length, upon which are arranged two canvas balloons kept taut by a wooden framework. One of these balloons is white and the other is black. Each is a meter in diameter, and is supported by a rod which is usually a meter in height. The vessels of the squadron successively fire their large guns at this target, which moves at a definite velocity. The shell, on dropping into the water, raises an immense jet, which entirely hides the balloons when the projectile falls in a line with and sufficiently near the target.

The smoke that envelops the ships, the thunder that echoes in the calm of the sea, and the jet that rises in the air produce a thrilling effect and give an idea of the power of man carried to the last expression.—L'Illustration.

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MODERN CAVALRY ON THE FIELD OF BATTLE.[1]

[Footnote 1: A lecture lately delivered at the Aldershot Military Society's library.]

By Col. R. S. LIDDELL.

I feel that some apology is due from me for coming down to Aldershot and giving my opinions before so many officers whose daily experience renders them much more capable than I am of bringing this subject forward, and it was with some hesitation that I yielded to the flattering invitation of the Military Society of Aldershot to read a paper here to-day on cavalry. At the same time, if it is thought that anything I can say can increase the success that this society has already met with, I can only add that I render my services most willingly. It seems to me one of the many advantages that these meetings possess is the bringing together of the different branches of the service, and the mutual information they afford of each other's arm. When we look back only a few years, we have much to be thankful for in the disappearance of a vast amount of prejudice that used to exist between the different branches. Each arm thought that theirs, and theirs only, was worth studying. Infantry officers sometimes said, as long as their arm was sufficiently numerous and well equipped, that, with the exception of a few scouts and orderlies, cavalry might be dispensed with. Artillery might think that unless guns were largely used, no infantry could ever make an attack at all; while cavalry officers, who were perhaps the most conservative of all, would point to the past, and show how every battle that had ever been fought was won by cavalry, and ever would be.

Confidence in one's own arm is most desirable, and should be fostered, if at the same time we can learn how to work with others, remembering that while cavalry gives the information to and hides the movements of the army, while artillery shakes and disperses the enemy's formation, and prepares the way for attack, it is the infantry alone who can assault and hold the position, and it is for their advance and to bring them up to the point that determines the battle in the condition most favorable to insure success that all the efforts of the other two arms must be devoted. I have made these preliminary remarks, as from my paper being entirely given to the actions of cavalry, it might appear that I am claiming more for that arm in the battle field than is reasonable; but I wish it clearly understood that whatever I may say is only in an auxiliary sense to the action of infantry, and I trust that I shall not be thought underestimating other arms, while showing unbounded confidence in my own.

The necessary rest required by Europe after the exhaustion of the wars of Napoleon resulted in the long peace which succeeded the campaign of 1815. This, and the improvement that took place in fire arms in the next forty years, gave room for speculation as to whether cavalry would play as important a part in the future as it had done in the past, under Marlborough, Frederick the Great, Napoleon, and Wellington. The Crimean war helped to confirm the opinion that the days of cavalry had gone by. No account was made of the enormous distance by sea that the cavalry had to be transported, the unfavorable nature of the seat of war for that arm, the little scope given in a campaign that resolved itself into a siege, the smallness of the cavalry force employed, and the difficulty in keeping up a fresh supply of horses. After this war came the introduction and improvement in the breech loader, and with it opinions were strengthened that cavalry duties would be still further limited, and its traditions for a time appear to have been lost.

The awakening from this transient period of theory came from a nation not trained to arms, and it is to the American civil war that we owe the revival that took place in the use of the cavalry arm. The raids made by the Confederates under Morgan, Stuart, Forrest, and by the Federals under Sheridan, drew attention to advanced cavalry work, such as scouting, reconnaissance, outpost and dismounted work. As particular examples we may select Morgan's boldest and greatest raid in 1862, when he passed through Kentucky and Indiana, capturing large stores from the enemy. By his rapid and skillful marches the Federal officers were completely bewildered. He was absent from his army 24 days, in which time he traveled 1,000 miles, capturing 17 towns and destroying all the government supplies and arms. In a second raid he forced the Federal army to fall back by taking possession of the railway in its rear which brought it supplies. In October, 1862, Stuart made his greatest raid through Pennsylvania, around the Northern army. He set out with 1,800 cavalry and four pieces of horse artillery, and crossed the Potomac. The telegraph wires were cut in all directions, railways obstructed, and a large number of horses captured, and all the public stores and buildings were destroyed. His position at this time was very critical, 90 miles from his own army. He considered it less dangerous to return by the opposite way to which he came.

Forrest used his cavalry in every possible manner, dismounting in the battle field and employing it as infantry. In October, 1864, during a raid, he impeded the navigation of the Tennessee River, which was filled with Federal gunboats. Choosing a strong position on the bank, he masked his guns and awaited the approach of the enemy's vessels. He captured a gunboat and a transport, and manned them with his own men; but his naval expedition did not last long. Pursued by several gunboats, he had to run his ships on shore, when the troopers gladly mounted their horses again. His object was, however, gained—inspiring alarm throughout the country and occupying a considerable number of the enemy. Later on the Federals copied this system, when the raids of Sheridan, with his 10,000 horsemen, armed with the magazine rifle and revolver, with sword attached to the saddle, brought about the final overthrow of the Southern army.

The next campaign that took place was in 1866, known as the "Seven Weeks' War," when large bodies of cavalry were used by the Austrians and Prussians. This campaign was of such short duration that there was not sufficient time for the experience gained in the use of cavalry to be utilized while the war lasted; but when the war was over, both sides, having bought their experience, set out to reorganize their systems, and the course pursued by the Prussians after this campaign in largely increasing their cavalry was fully justified by the advantages reaped in the war in France in 1870. At the close of the Franco-German war the attention of the whole of Europe was called to the successful use of German cavalry during the campaign, more especially the advanced duties, when at times 60 miles in breadth and 50 in advance of the army was covered by the cavalry.

In England, after the termination of this war, many German military works of great value were translated and published; the battle fields in France were visited and described; every movement of both armies, strategical and tactical, was studied. All this tended to draw our attention to the extended use of the cavalry arm in future campaigns, and the shortcomings of our own system were carefully scrutinized. The movements of our drill book were simplified, the careful training of our men in shooting was more fully recognized, and the teaching of advanced cavalry duties, reconnaissance, outpost and dismounted work, were gone into most thoroughly—in such a manner that I may confidently appeal to those officers who have the best opportunities of forming an opinion, whether our cavalry does not bear comparison now with what is being done in other armies, and in these matters is advancing in a satisfactory manner. While all this good work has been going on (and I would be the last to say one word that might seem to depreciate its value) we may perhaps have permitted the action of cavalry on the field of battle to escape from sufficient notice.

It is for this reason I will ask your permission to bring before you this subject, believing that the opinions of all branches of the service being brought to bear upon it, considerable advantage maybe obtained. It will be my endeavor to show, not by my own arguments, but by quotations from others, that cavalry still has an important part to take on the battle field, and far from its duties ending when armies come in contact, that it is still reserved to them, as has been the case before, to decide, perhaps by only one charge, the issue of a whole campaign. Prince Kraft in his letters on cavalry says: "The battle of Mars-la-Tour, won by the bold employment of cavalry, made possible the blockade of Metz, and afterward the surrender of the whole of Bazaine's army. So it may be said, without exaggeration, that the charge of Bredow's six squadrons on that day was the turning point of the Franco-German campaign."

Colonel Home, in his "Prcis of Modern Tactics," says: "The action of cavalry on the actual battle field is by no means a thing of the past. The use of cavalry with skill at the right moment and in the right numbers has always been considered one of the most difficult problems in war. Modern arms have increased this difficulty manifold, but to say the day of cavalry on the field of battle is past is merely another way of saying that the knowledge of how it should be used is wanting." Cavalry is apportioned to an army in two capacities: (1) Divisional cavalry, that is (if possible) a regiment, or as many squadrons as can be spared, attached to each infantry division, acting under the orders of the general of the division. (2) The cavalry division, that is, a large body of cavalry composed of several brigades, an independent body having its own commander. On the march the divisional cavalry covers the head and flanks of its own division: on the field of battle it will be as near as possible to its division, in the most sheltered spot that can be found; in the early part of the battle it would be kept as much in reserve as possible, cheloned in rear of one flank of its own infantry. It would remain there until the artillery and musketry had effected their work, and the enemy's flanks had become thinned and shaken. Then, when his infantry become tired and exhausted, under cover of the smoke, the cavalry may be further advanced.

Prince Kraft says: "At Sedan the divisional cavalry were employed during the battle, charging by single squadrons, patrolling and reconnoitering to obtain information of the enemy and the ground. Every infantry body is accompanied by patrols, however small." An instance of the too early employment of cavalry in a battle occurred at Waterloo, when Napoleon at the commencement launched his cavalry into the fight. The result was that although it far outnumbered the English at first, it became so reduced, depressed, and worn out, that it was unable afterward to offer full resistance to the British squadrons, who were comparatively fresh. Wellington, on the contrary, after his first successes, kept his cavalry, as much as possible, in reserve. The field of battle itself shows the proper situation of cavalry, but the divisional cavalry on the defensive side must always be at hand to fall upon the flanks of the enemy's infantry when in extended order, while that of the attacking side must be equally at hand to prevent the flanks of its own infantry being so attacked.

In discussing the action of divisional cavalry, the most advantageous time for its assisting in the combat must be considered. At what moment, if any, can infantry be attacked by cavalry? When opposed to a force acting on the defensive, divisional cavalry has its operations limited, and probably in the earlier part of an engagement, confined to watching, and, if possible, guarding the flanks of its own attacking infantry from surprise. It is the cavalry on the defenders' side that has the greatest opportunities. In both cases, however, a rule must be made not to attack infantry when it has taken up a favorable position, or before its ranks have been shaken by artillery or musketry. Prince Kraft, in speaking of Mars-la-Tour, says: "This same day took place a series of cavalry charges of greater or less importance, which all showed practically to the cavalry the limits of their effective action against infantry. The advancing infantry were brought to a stand, infantry who gave way were ridden down, but where the cavalry attacked infantry intact, the cavalry were unable to prevail."

The precision of modern fire arms has necessitated great changes in infantry tactics. To advance against the murderous fire of the present rifle, infantry is compelled to adopt scattered formations in small lines, and to move forward with sudden rushes. All this lends itself to the attacks of an active cavalry. When these infantry attacks take place, it may be presumed that they have already been under arms some hours, have marched some distance, and been exposed to considerable loss from artillery and musketry fire. Their advance in extended formation will have commenced at about 1,000 yards, or earlier. By this time the squadrons opposing them will have been brought to a more advanced position, to the nearest point to their flank where cover is afforded, and to carry this out successfully requires skillful handling. Files must be extended, and short rushes made with small bodies, say half a troop if over exposed ground, into sheltered places. It is true that cavalry cannot hide themselves over exposed ground as infantry can, but they have one advantage that nothing can deprive them of—rapidity of motion; and the distance that would take them say 10 seconds to traverse, viz., 150 yards, would take infantry a minute.

Prince Kraft writes: "No battle field is a tabula rasa, for in the most exposed country there are depressions. If strong skirmishing lines of infantry can advance directly over a country devoid of cover, cavalry can undoubtedly do the like, if by making use of the lie of the ground they can gain the enemy's flank. A skilled cavalry leader will thus undoubtedly find an opportunity to get close to the enemy." Having arrived at this more advanced position, say from 500 to 1,000 yards, according to the formation of the ground, the nearer the better, the most favorable moment to assail the flanks of the attacking infantry would probably be immediately before the last belt of the fighting line, and before the main body had re-enforced them, as they are preparing for their last united rush, and as their supports are doubling up to join them.

At this moment the men would be to some extent out of breath, their attention would be fixed on the point about to be attacked, and their flanks would be neglected. Cavalry should then descend upon them at the utmost speed that can be extracted from the horses, with a good interval from knee to knee. If there is only one squadron, one troop should take the flank or fighting line, while the other throws itself upon the support. As the distance to be covered in the open will probably be not more than from 200 to 400 yards, they will be exposed to fire, supposing none of the ground is undulating, for fifteen to thirty seconds when at full speed. As they close on the infantry neither the supports nor those in rear of them or their artillery will dare to fire, on account of their own men. If the infantry run to get into small squares, as is most likely, the cavalry must endeavor to catch them before they assemble. If they get together it may be too late for the cavalry to stop. They must then throw themselves upon them and trust to the supporting squadron to complete the attack.

Although it is rare that a battle field is on such ground that there are no undulations to afford shelter for cavalry in an advanced position, this may be the case, and if so the enemy's infantry attack must be allowed to take place, but even then, by cavalry showing itself on the flanks for a moment, infantry would get together and afford a better mark for fire, and the progress of the attack would be delayed. The very appearance of cavalry frequently frightens infantry into masses. If the ground was too much exposed for the charge, men might be dismounted, with their carbines, at a safe distance to assist the infantry. If mounted infantry were at hand, they would be utilized in the same way, and the machine guns of the cavalry would also pour in their volleys. If the enemy's attack is successful, cavalry must then advance on their flanks and take its chance, and if necessary sacrifice itself to give its own infantry time to rally. If it is unsuccessful, the cavalry must be ready to take every favorable opportunity of molesting its broken ranks.

Speaking of Mars-la-Tour, Prince Kraft says: "During the battle a German infantry brigade was forced to retire with heavy loss, and ran some danger of being annihilated by the pursuing enemy. But the First Dragoons of the Guards threw themselves on the pursuers. The enemy's infantry massed round the eagles and ceased to press on, while the thin ranks of our infantry were able to rally, and our guns were saved and brought into position. The losses were heavy; half a regiment of cavalry (250 horses) were sacrificed in order to save the brigade." At Waterloo a French division of infantry fled before three regiments of dragoons (the Union Brigade). The Royal Dragoons and the Inniskillings in first line, the Scots Greys on their left rear, the whole under Sir William Ponsonby, acting in support of the Highland Infantry Brigade, were awaiting the attack of the whole of the 1st French Division under Gen. Alix. The three Scotch regiments threw into them a concentrated fire, and as they were staggered by the shock Ponsonby gave the order to advance. Passing through the Highlanders, the Greys having come up into line, the three regiments charged the leading portion of the French column, which yielded, and those in rear were hurled back. The dragoons having the advantage of the descent of the hill appeared to mow down the mass, the Greys on the left pressed on through the supporting brigade of the French, while the Royals drove back the right, giving no time for fire. Many threw down their arms, while hundreds of prisoners were hurried off to the rear of the line. At the same time the Inniskillings forced their way through the center, when the remainder of the French division broke and fled.

It may be said that this took place before the introduction of the rifle, and is therefore no example, but it took place within the range of the weapon then in use, and at that distance it was equally effective. The celebrated charge of Bredow's brigade at Vieuville (Mars-la-Tour) also shows what an energetic attack may do. It had become necessary to demand a sacrifice from the cavalry for the good of the army, to enable Prince Frederick Charles, with only 24,000 infantry, to hold in check Bazaine's army of 180,000 until his own main body came up. Bredow's cavalry brigade consisted of six squadrons of the 7th Cuirassiers and the 16th Uhlans. They were ordered to make a breach in the front of the 16th French Army Corps.

The six squadrons advanced in column, the cuirassiers leading, when they received the word to change direction to the right, then to form line, which was done under heavy fire. The cuirassiers getting into line first, charged at once, the 16th following in echelon. In a moment the batteries, vomiting flames, were reached with a loud hurrah, and the gunners cut down at their guns, when the whole brigade, which had now got into one line, charged the long lines of infantry in rear, who received them with a heavy fire from their chassepots. These lines, too, were broken through, and the main object of the charge was attained, but, carried away by the ardor of the combat, they charged and took the mitrailleuses, when the French cuirassiers, with a dragoon brigade in support, come down upon them, and compelled them to fall back. This they did, having to force their way back through the enemy's masses of infantry with enormous loss. The object, however, was gained, and the attack of the French corps checked and never resumed. The cavalry division covers the advance of the whole army, and is a day or two in front of it. It conceals and guards the army, while finding out the movements of the enemy. It collects information, and is also used with horse artillery on great enterprises on the enemy's communications. Having finished the reconnaissance and covering the army on the day of battle, it falls back as the two opposing sides come in contact, and awaits further orders. On the battle field it should be placed so as to suffer as little loss as possible—as a rule, in rear of the flanks. How far must depend on the formation of the ground; if shelter is to be obtained nearer the front, the better. If not, then some 2,000 yards in rear of one flank would seem advisable. Its duties are to guard the exposed flank or flanks and rear of the army, while it watches the cavalry of the enemy. If within range of artillery, it should be kept on the move from front to rear. Its strength should not be wasted or frittered away on doubtful enterprises, as it maybe required for some decisive blow, in pursuit, or in covering the retreat.

Prince Kraft, speaking of the battle of St. Privat, says: "On the 18th of August the gigantic fight of St. Privat took place. The cavalry divisions were held back in reserve, but the divisional cavalry took an active part. During the battle a squadron of hussars advanced and sent information of the enemy making a flank movement." He also says: "At Sedan the cavalry division was kept in reserve." The massing of artillery at the commencement of a battle must expose a long line with some weak spot to attack. If protected by cavalry, then probably a cavalry combat will ensue. Prince Kraft says: "The action of the masses of German cavalry at Mars-la-Tour excited wonder and admiration; they surprised the enemy's cavalry when in bivouac, they met and surrounded the hostile infantry in a threatening manner, and thus 8,000 cavalry occupied 65,000 infantry, until the Prussian infantry came up. The cavalry made no charges which could not have been successful, but carried out their task of occupying the enemy almost without loss.

"In the old days these squadrons would have charged and ridden down the infantry. The change is the result of the improvement in fire arms." During the early stages of a battle, advanced parties, under officers selected for the purpose, must be kept out from the cavalry division to watch the enemy's movements, and the information they should be able to afford should be invaluable to the general-in-chief. An engagement with the enemy's cavalry should not be sought unless they are much weaker; but should the necessity arise, the ground should be reconnoitered, and every advantage of position taken to insure success. The attack being determined on, the preparations for it should be carried out rapidly. Echelon movements have many advantages. They favor the formation of oblique lines, they also insure in a charge direct to the front the bringing up of squadron after squadron in support. The attack of Vivian's Hussar Brigade upon the French reserves at Waterloo gives a brilliant illustration of this, and has been termed by Siborne the "crisis of Waterloo." This celebrated charge, intended to be in line, became virtually a charge in echelon of squadrons in consequence of the rapid pace of the head of the column.

"The movement of cavalry must be rapid and unexpected, and bear the character of determined confidence; an effort should be made by maneuvering to come suddenly on the enemy's flank. A gentle declivity for the final charge must be sought. The rapid, vigorous, and determined charge in line on to cavalry, riding knee to knee, is what is required." The charge to be made effectual, the horses must be brought up in wind, the gallop must not be begun too early; when begun it must gradually be increased to a fast gallop, the final charge for the last sixty yards made with every horse extended. "Nothing, then, must be left undone to excite the spirit of enthusiasm, even to ferocity; then, and only then, the 'cheer' to be raised." At Waterloo the charge of the heavy brigade, the 1st and 2d Life Guards and King's Dragoon Guards, with the Blues in support, is a good example of a successful attack on cavalry. The French line of cavalry as it advanced presented an imposing appearance.

They had ascended the brow of the ridge, when a vigorous fire from Ross' Horse Artillery was opened on to them. In the next moment their trumpets sounded the charge and they rushed to the attack, and as cuirassiers approached the British squares, the Heavy Brigade dashed into them. The shock was terrific. The right of the Life Guards being thrown forward, came first into collision. The right of the French was suddenly thrown out by coming unexpectedly on to a hollow way, and as they passed it the 2d Life Guards came full speed upon them. The French cuirassiers were driven back and pursued until the English brigade came under infantry fire.

The charge of the Heavy Cavalry Brigade at Balaklava, under Gen. Scarlett, is another good example, when the Russian cavalry, receiving the British charge at a halt, were entirely overthrown. One of the greatest difficulties after the charge is to know when and how to stop, and it is then that the squadron and troop leaders, well in front of their men, must use all their efforts to carry out the ends of their commander. I think this is the time when a strong whistle carried by the commanding officer and the squadron leaders can be used with good effect. Being an unusual sound, it would attract attention. The battle being over, some of the most serious duties of cavalry commence. If the enemy is victorious, the pursuit has immediately to follow. History points out the difficulty of carrying this out. Uncertainty of the victory, or how far it can be counted on, often delays its commencement. Battles are often ended by nightfall, valuable time is lost, and the golden opportunities are past. An active cavalry leader will, however, without further orders at least, follow with his advanced parties and not lose touch of the enemy. He will soon learn the condition of the enemy, act accordingly, harass his flanks and rear and play upon him with his artillery.

An example of another manner in which cavalry may be employed after a victory can be taken from the Egyptian campaign of 1882, when, after the battle of Tel-el-Kebir, by a rapid advance of the cavalry some fifty miles ahead of the infantry, the capital of the country was captured by the English cavalry division.

If the battle is lost, still greater are the responsibilities of the cavalry. Detached squadrons with scouts must be sent round the flanks to ascertain the strength of the enemy sent in pursuit. Every available position must be taken up by the horse artillery, and every advantage seized for counter attack. Above all, accurate information must be obtained for the general-in-chief of the nature of the pursuit, in order that he may not harass his main body by falling back further than necessary. This subject, however, is beyond the scope of this lecture, and is one of study of past campaigns.

Of the action of cavalry in savage warfare, the recent campaigns in Africa have given some experience. In the presence of an enemy met with in such enormous numbers as in the desert, cut off from all help, knowing that unless you win you die, it seems to be decided that our infantry must adopt the square as the most suitable formation. In the Zulu war, the cavalry at the battle of Ulundi was placed inside the square. The experience met with there was exceptional, and from the swarms of savages surrounding the square in all directions it was considered desirable to keep the 17th Lancers in the center of it, in order that they should not interfere with the infantry fire, and that when the enemy was repulsed, they should be launched out upon them, and this was done with perfect success. It is, however, contrary to the instincts and traditions of cavalry to be shut up in a square, and, where practicable, I should think cavalry outside a square, even at some distance out of the way of the infantry fire, acting with horse artillery, would very much disturb the attacking bodies of the enemy, and perhaps attract away a portion of them, and they could be brought up, when called upon to do so, to carry out the pursuit.

In the first campaign on the east coast of the Soudan, on the advance to El Teb and afterward to Tokar, squadrons were sent in front and on the flanks of the square with scouts thrown out to feel the way and obtain information, while the main body of the cavalry was echeloned on the rear and flank opposite an angle of the square in the most suitable manner to avoid any interference with its fire. During the action it remained in this position until after the first attack on the square, when it moved away past the square on the outward flank and acted on the enemy's rear and engaged their reserves until the action was over. During the desert march in the Nile expedition, the 19th Hussars, by its scouting, protected the square and gave it timely notice of the approach of the enemy.

In a country where a great deal of bush abounds the effective charge of cavalry on to groups of savages is very much curtailed. The Arabs throw themselves on to the ground behind the prickly bushes, the ranks are opened out as the horses avoid the thorns, and the men get no chance of using their swords; but although much execution is not achieved under these circumstances, the natives have great fear of cavalry, and they are prevented from attacking elsewhere. When their attention is thus occupied, horse artillery and machine guns might make great havoc among them. At the action of Tamai, where the ground, from the rocks and ravines of the neighboring mountains, was unsuitable for cavalry charges, when one of the infantry squares was broken, the cavalry advanced, and one squadron of the 10th Hussars, dismounting, helped to create a favorable diversion by pouring fire into the flanks of the attacking Arabs.

My remarks would, I think, be considered incomplete if I did not touch on the question of cavalry charging squares, as this point is always made very prominent in all discussions on the action of cavalry. I therefore must not pass it by. I will say at once that I think it most undesirable, even under favorable circumstances, that cavalry should charge a formed square and men armed with the breech loader. At best the gain can be but local and partial, while the loss to the cavalry—an arm so difficult to keep up in numbers—must be disastrous, and it seems to me that if cavalry by its appearance can force infantry to form square, it has done enough, and that the artillery, infantry, and machine guns should do the rest. The necessity might, however, arise, and by looking at the past we see its possibility. At Langensalza two Prussian squares were broken by the Hanoverian cavalry, and the major part taken prisoners.

We have only to turn to the recent campaigns in Egypt to see the effect of determined rushes of men, intending to succeed, charging on to squares carefully formed on ground affording shelter, with an enormous amount of fire being poured upon them. It will be said that these men were fanatics, but our cavalry, too, have been, and will be, fanatics in a charge; and I still think, if the necessity recurs, that an attack, properly conducted on favorable ground, one troop charging on the corner of a square, followed by another at double distance, others in echelon on both flanks immediately following, the whole charging with the greatest impetuosity, intended to win, will break down any square that Englishmen are likely to meet with. If we look back again on the past, we will find many instances of British cavalry not being called upon in vain to make a sacrifice. At Talavera, the 23d Light Dragoons, supported by the 1st Hussars of the German Legion, advanced against the French squares. In their impetuous rush they came upon a hollow cleft covered with long grass, eight feet deep, and eighteen feet broad. Too late to pull up, the foremost rode headlong into it, some tumbled in, others over it, some rode boldly at it and gained the other side. Still they went on, swept past the infantry columns, and fell upon a brigade of French chasseurs.

At Balaklava 670 British horsemen were launched against an entire wing of the Russian army. The brigade, at first in two lines, the 11th Hussars, 17th Lancers, and 13th Light Dragoons, followed by the 4th Light Dragoons and 8th Hussars, advanced down a gradual descent of three-quarters of a mile; the Russian guns vomiting shell and shot upon them, one battery bearing on their right, another on their left, and all the intermediate ground covered with riflemen. The guns were charged and forced through, the forces drawn up in rear were overpowered. They then had to turn, and, retiring up hill, ran through the same gauntlet. In the Sikh war, at the battle of Ferozeshah, the 3d Light Dragoons charged the enemy's entrenchments at a point defended by some of their heaviest batteries. When within 250 yards the regiment moved at speed under a destructive fire of grape and musketry, and pressing forward at the charge entered the enemy's camp and captured the whole of the batteries.

Cavalry attacks have been made with success after dark, and the advantage, of course, is gained of obviating opposing fire. Prince Kraft mentions that after the battle of Mars-la-Tour, the cavalry division, re-enforced by the divisional cavalry, rode forward to complete the advantages gained. It was almost night, and fault has been found with making the attack in the dark. If the ground is well known a night attack may be advisable. While criticising it, we have to think of the feelings of a half-defeated army about to bivouac being attacked by unknown forces in the dark. In this case, at Vionville, the enemy did not wait for a second, but withdrew, and abandoned the whole field of battle. Prince Kraft quotes the attack of Blcher at Gross-Gorchen and a cavalry attack at Loon. During the first Egyptian campaign the Life Guards made an attack by moonlight at Kassassin.

I have now, I think, touched lightly on some important cavalry duties on a campaign. In some points perhaps these remarks may appear contradictory. How to combine keeping cavalry in reserve for any great action it may be called upon to perform, while using it unsparingly to assist on the battle field, if the necessity arises. It may, however, be noticed that, much as they may be criticised, few cavalry commanders have been severely blamed when they have thought it best to take the bolder course. To insure to cavalry the power of carrying out its duties successfully in war, organization and practice in peace is most essential. Infantry may suddenly be increased without much deranging its action in the field, but cavalry cannot be hurried into an increased augmentation. In tactics simplicity in every evolution and rapidity in execution are the most important principles. This simplicity of drill, I think, might be assisted if our squadrons were divided into four divisions, zuges, or pelotons. When squadrons have 48 files in the front rank there might be four of these, while weak regiments with 36 files could drill equally as well with three divisions. This system, introduced by the late Gen. Valentine Baker into the English service for a time, and now used by all European countries, was found to work well.

I think the whistle could be carried with advantage by all cavalry officers. For advanced work attention can be drawn by it without being heard at a distance like a bugle. In movements the commanding officers would find it useful to call the attention of leaders to himself, especially in extended or chelon formation. I have omitted to make much mention of the action of horse artillery combined with cavalry, as it seems beyond the limits of this paper; but it is one to which the cavalry officer's attention requires to be brought most strongly to bear. I would also have wished to have made some remarks on the many advantages to be obtained by having mounted infantry attached to cavalry. I understand that this force would be under the orders of the cavalry general, and if so, I think a cavalry division well found in horse artillery, with mounted infantry, whether conveyed on horses, or, where the cavalry admitted of it, on cars, and accompanied by machine guns on wheels, could act in such an independent manner as to enable it to penetrate far ahead into an enemy's country, or threaten his communications, and be absent from its main body for many days or weeks.

As regards the English cavalry, I think it may be said, without boasting, that the material is excellent. The men are of the best physique, recruited from a good class, and plenty of them to be had. The non-commissioned officers are intelligent and always ready for instruction; the riding compares favorably with cavalry of other nations, certainly far better than any I have ever seen abroad, either German, Russian, or French, and among all foreign countries we have the reputation of being the best horsemen in the world, which at all events has a good moral effect. Our horses are undoubtedly first-rate, having more quality and greater speed than foreigners. We have in our officers the exact stuff we want. Their very sports and amusements start them with all the makings of cavalry soldiers. But the quickness of eye, the self-confidence and readiness that these sports and games may give, require nowadays more than ever something beyond this to produce the trained cavalry leader. Cavalry is an arm of opportunity, and above all others depends greatly on its leaders, but with the chances now available of reading, in every detail, the campaigns of the past, if taken advantage of, as is now daily becoming more common, we should produce in the future the best and most accomplished cavalry officers that this country or any other has ever seen.

As there appeared to be a unanimity of opinion on the lecture, there was no discussion, and the proceedings closed with a vote of thanks to the lecturer.—Broad Arrow.

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IRON SAILING SHIPS.

Messrs. Russell & Co., Greenock and Port Glasgow, show at the Glasgow exhibition a very numerous and varied show of sailing models. First, we find the noble four-masted ships of from 1,800 tons to 2,200 tons, which sail and carry well on their tonnage, and which are worked by fewer hands than are required for a ship of the same burden with three masts but squarer yards. Some owners prefer the latter, and so Messrs. Russell show not only such handsome specimens as the four-masted Falls of Earn, but also the three-masted Ardencraig and Soudan. One of the favorite models of this firm is that of their 1,500 ton ship with three masts, represented by the Cromartyshire, of which type they have built a large number of vessels noted alike for their carrying capacity and their excellent sailing qualities. The Main, built for Mr. James Nourse, of London, is a good specimen of their 1,700 ton ship, as designed for the special trade of the owner, between Calcutta, Demerara, and London. Their 1,300 ton bark is represented by the model of the Aboukir Bay and her sisters of the Bay Line, owned by Messrs. Hatfield, Cameron & Co., of Glasgow; while their 1,000 ton barks are shown in the model of the Banca, belonging to Messrs. P. Denniston & Co., of the same city. These are about the smallest class of sailing ships built during recent years, the demands of the shipping trade being such as to make it unprofitable to sail anything smaller than about 1,500 tons; while the tendency is to exceed 2,000 tons in burden, and to reach even as high as 3,000 tons.—The Engineer.

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WATER BLAST PUMP.

It is well known that the principle which is applied to the construction of vacuum or filter pumps, and which aims at the production of rarefied air in a certain inclosed space, may also be applied to the production of air pressure.

A simple apparatus by which this may be accomplished has recently been constructed by A. Beutell.

A tall cylindrical flask, K (see cut), is provided with an outlet tube near the bottom, and its stopper carries two tubes, one (M) for the entrance of a jet of water, and the other (L) for the exit of the compressed air, which may be conducted to a blast lamp or wherever air under pressure may be needed. The column of water entering through M causes air to be sucked in through the little hole at c, and this air, after arriving in the flask, is gradually compressed by the continuously entering water.

In order that the apparatus may work properly, it is necessary to construct the tube, M, in a particular manner, and of certain definite proportions. Fig. 3 exhibits its bore and shape in an enlarged view. A short distance below the orifice of the tube it is slightly expanded, and then gradually contracts to the place, b. It then again expands to an oblong cavity, and contracts again to a neck, e, which is a trifle wider than that at b, and which must be so situated that the column of water passing through b is exactly perpendicular to the center of the aperture at e. The tube then expands again to its original diameter, and is slightly curved, which is done to prevent any of the compressed air in the cylinder, K, from regurgitating upward.



The outlet tube at A is preferably constructed as shown in Fig. 2. Instead of being made of one piece, it is there represented as consisting of two pieces joined together by rubber tubing, a sort of check valve, G, being introduced into the rubber joint. By regulating the check valve, that is by approaching it more or less to the exit of the tube, A, the outflow of water may be regulated. It is important to adjust this so that the cylindrical flask will always be at least half full, and never over three-fourths filled. While the column of water falls through the aperture at b, into the expanded portion of M, it aspirates air through the little orifice, c, communicating with the outer air, and this air is carried along with it into the flask, where it accumulates until it is under a pressure equal to that of the column of water entering the apparatus, when the latter will cease to flow. By allowing the air to escape through L, more will be successively compressed, so that a steady blast may be obtained.

The proportions between the diameters of the expanded and contracted portions of the glass tube, M, are important. If the bore at b amounts to 2.5 millimeters, that at e should be 3 millimeters. Under these circumstances, and with a pressure of water equal to a column of 61.7 cubic centimeters, the apparatus will furnish 890 liters of air for every 1,000 liters of water consumed. If the two diameters were: b, 1 millimeter, and e, 2.4 mm., one liter of water aspirates 2.35 liters of air. These proportions are, no doubt, capable of improvement.—Chem. Zeit. and Ch. Centralbl.

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TRANSMISSION OF POWER BETWEEN BODIES MOVING AT DIFFERENT VELOCITIES.

A few months ago there was exhibited, in the society's reading room, a working model of an application to railway working of what the inventor calls "division of the mass." In causing a body, moving at a high velocity, to communicate motion to another at rest, or moving at a lower velocity, he splits one of them up into parts all the more numerous, and therefore tenuous, as the difference in velocity is greater; and this is accomplished by causing one of the parts to take the form of a brush composed of metal fibers.

In applying this principle to the transmission of motion for driving machinery, a disk, fitted with segmental brushes, is slid laterally along the shaft, so that the fibers come into contact with radial projections on a second disk; and, although the contact is made instantaneously, the action is exerted gradually, owing to the flexibility of the fibers. That is to say, the full power is communicated without any shock.

A similar arrangement, but with one of the disks fixed, serves as a brake for arresting motion, and this again without shock, but with gradually increasing action. Where space is very much circumscribed, the clutch and the brake may be combined, by fitting a disk with brushes on one side, and projections on the other, so that it may be brought by a lever against a second disk, for transmitting motion, and against a third, fixed, for stopping it.

Safety appliances for arresting the descent of mine cages, in the event of the rope breaking, have hitherto depended upon the entrance of claws into the guides, or the clipping of the latter, or the wedging of the cage between the guides.

In this application of the system, the guides of the shaft are fitted with corrugated iron plates, and the sides of the cage with steel brushes. In the normal state of working, the brushes are kept clear of the guides, but, should the rope break, a small brush, fitted on a sector, constantly rubbing against the corrugations of the guides, aided by a spring or counterweight, brings the main brushes into contact with the guides by a link arrangement, like that of the parallel ruler, thus arresting the cage, and holding it suspended until the brushes are gradually relaxed, for "braking" the cage slowly down to the next landing.

Many attempts have been made to cause a locomotive, running at full speed, to exert such a mechanical action as would set a signal to danger, so as to protect the train from another following in the rear. By fitting the engine with a steel brush, attached to the axle boxes, so as to preserve a uniform height with respect to the rails, a stationary lever may be gradually moved, so that the signal is set at "danger" without shock. Moreover, by means of another brush, in the event of the engine being turned upon the wrong line, a lever may be made to shut off the steam, apply the brakes, blow the whistle, or move an index on a dial, recording a neglect of duty, or may exert these four actions simultaneously.

All the above applications of this principle—"the division of the mass"—have been tested experimentally, the last named by the model above referred to. The clutch arrangement has transmitted six horse power from a petroleum motor, making 200 revolutions a minute, to a dynamo making 2,000 revolutions, while applications to industrial purposes are now being made, both in this country and in Belgium. The inventor of the system is M. Raymond Snyers, Ingnieur des Mines, du Gnie Civil, et des Arts et Manufactures, of the Louvain University.—Journal of the Society of Arts.

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STEAM GENERATOR OF SERPOLLET BROTHERS, PRODUCING STEAM INSTANTANEOUSLY.

The explosibility of a steam generator may be measured by the relation of its total capacity to its vaporizing power. The old fashioned generators and some of the modern ones are so constructed as to contain from fifteen to twenty times more water than they are able to vaporize within one hour. Thus a great quantity of heat is obtained and a uniform pressure assured, but the steam-generating apparatus is costly, heavy, and cumbersome; it requires a long time before the necessary pressure is obtained, and the generator is only suitable for a stationary installation and where it can uninterruptedly work for a long period of time. Besides, the enormous quantity of hot water under pressure constitutes a constant danger, and the explosion of a steam generator with boiler tubes becomes a real disaster.

In order to satisfy the requirements which have newly arisen in connection with navigation, locomotion, small motors and apparatus which need for their working an intermittent supply of steam, it became necessary to modify the construction of steam boilers, to augment their heating surface, to diminish their residue of water, and to gradually construct so-called inexplosible apparatus, of which the Belleville boiler forms one of the most characteristic prototypes.

In trying to reduce the inexplosibility to the utmost, Messrs. Serpollet Brothers have succeeded in constructing a type of boilers which may be called absolutely inexplosible, and this result has been obtained by reducing the capacity of the boiler to practically nil, thus rendering the explosibility also nil, for under the circumstances the relation between capacity and vaporizing power becomes itself nil.



The method employed for this purpose by Messrs. Serpollet is an extremely simple one. A cylindrical steel tube of convenient diameter and sufficient thickness is rolled flat at a temperature below the white heat of the metal, and the last touch of the rollers is given to it when already cold. By this means a flat tube is obtained, the empty interior space of which looks in a cross section (Fig. 1, No. 2) like a black line not thicker than a hair, and measures from 0.1 to 0.3 millimeter. This tube is finally rolled up in the form of a spiral, or left straight, according to the use to be made of it, and put into an appropriate furnace (Fig. 1, No. 1). To either end of the tube a joint is attached, the one for the purpose of admitting the water, the other for admitting the steam.

When under these circumstances the tube has been heated to a high temperature in a convenient fire box, the water which has been pumped into it, by a feed pump fastened to one of its extremities, is instantly changed into steam and escapes at the other end at a pressure and in a state of dryness depending on the working conditions of the apparatus. The ingenious and really original and novel idea in this invention is this flattened tube, which constitutes an actual capillary boiler inside of which the water squeezed in between its walls cannot assume its spheroidal state, and the formation of drops becomes absolutely impossible. There exists no longer a residue of hot water, nor are water gauges, safety valves, or any other of those numerous accessories required which make all steam boilers so complicated and which augment considerably their cost.

It also becomes unnecessary to connect the joint from which the steam escapes by means of a valve with the motor for which the steam is to be used. If the supply of steam is to be stopped, this can be done by simply suppressing the supply of water, i.e., by emptying the boiler.

The regular working is assured by the quantity of heat contained in the heated iron tube, to which, for this purpose, an intentionally great thickness has been given, and it is this heat of the iron which replaces the heat furnished by the hot water in the steam generators with boiler tubes. From the above it will be easy to understand the general arrangement of the new steam generator, when connected with its motor. This motor works a small intermitting pump, which supplies the capillary boiler with water, according to the quantity consumed. The machine is started by means of a small special pump worked by hand.

Whenever the velocity of the motor tends to increase, a centrifugal regulator placed upon the motor reduces the action of the pump and, consequently, the supply of water to the tube, thus checking the velocity of the machine. If the velocity tends to slacken, the inverse process is employed. In order to stop the machine, it suffices to turn off the water furnished by the pump by means of a three-way cock, and to send the water back to the reservoir of supply. The boiler can be emptied in less than a second, and the motor stops in consequence of being deprived of motive power.

The whole is marvelously simple, and creates astonishment and admiration in the mind of even the most skeptical persons who see the apparatus.

The boiler of the one horse power type weighs 33 kilogrammes. It consists of an iron tube having a length of 2 meters and a height of 10.5 centimeters after it has been flattened; the total heating surface thus obtained being 48 square centimeters. The power of vaporization amounts to 20 kilogrammes of water per hour, while the quantity of coal consumed during the same period amounts to only 4 kilogrammes, which is comparatively little for a boiler of so small a power.



Fig. 2 shows the first model of a tricycle constructed by Messrs. Serpollet as an application of their boiler for locomotion. The writer has seen the working of this apparatus, and consequently is able to give some data. The total weight of the machine is 185 kilogrammes, or about 250 kilogrammes when mounted by a person. The boiler is placed behind the tricycle, the motor is under the seat, inside of which is the water reservoir and the supply of coal. In the motor employed in the present case the feed pump is a constant supply pump, but by means of a directing lever turning around its own axis and acting upon a three-way cock, the water can be divided into two streams, the one emptying into the feeding reservoir, the other into the boiler. By varying the position of the cock, the power of the machine can be modified and its velocity regulated. The machine can be brought to a stop within less than two meters by means of the combined action of a brake and the complete suppression of water in the boiler. In order to start the machine, the water is sent into the tube by a little extra pump worked for a moment by the left hand of the cyclist when starting.

On July 25 some experiments were made before the Society of Civil Engineers with the tricycle above described, and on that occasion it traversed the Rue Girardon and the Rue de Norvino to Montmartre (streets in which the gradient rises to 15 centimeters per meter) with a velocity of three meters per second.

Fig. 3 represents the arrangement of the first stationary boiler of the new kind. The letters of reference will suffice to indicate the position of the principal parts of it, the forms of which may be varied according to the object for which the boiler is to be used.



Messrs. Serpollet are occupied at present with studying the special arrangements which will be needed for connecting their boiler with a quadricycle, a torpedo boat, a stove, a locomotive, or a stationary machine of 10 horse power, and with rectangular parts.

The inexplosibility of their boiler has been tested during an experiment made before the engineers of mines, on which occasion a manometer (steam gauge) graduated for a pressure of upward 200 kilogrammes per square centimeter was used, and the pressure raised far beyond the limits indicated. The result was that the hand of the manometer, being pressed against the walls of the box, became bent, and though the boiler was submitted to a pressure the degree of which it was impossible to measure, it was not changed in the slightest.

Incrustation of the boiler is not to be feared, for, in consequence of the great velocity with which the steam circulates through the tube, the solid matter dissolved in the water becomes pulverized and is forced out, mechanically assisting to lubricate and polish the parts of the motor.

The invention of Messrs. Serpollet is still too new to foretell all its possible applications, but their apparatus, in its present form, is exactly the steam generator which will be useful for producing a small motive force; while it will be necessary to wait until it has been ascertained, by further study, how the system can economically be used for high motive power.

The most natural and immediate application of the invention seems to be its use for the electric lighting of restaurants, in which case one of the instantaneous vaporization tubes might be connected with stoves which remain lighted all day, and which might thus besides supply the necessary motive force to work a small dynamo charging some accumulators.—E. Hospitalier, in La Nature.

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GAS LIGHTING BY HIGH-POWER BURNERS.

In the course of a communication presented to the Societe Industrielle du Nord de la France by the manager of the Wazemmes Gas Company, he made the following remarks on gas lighting with high-power burners:

For gas of a standard illuminating value, the lighting power increases with the temperature of the flame. It also increases, under favorable conditions, if the quantity of gas consumed by the burner in a certain period is augmented. Thus, two burners consuming 60 liters (rather more than 2 cubic feet) of gas, placed in juxtaposition, produce less light than one burner consuming 120 liters. As it is impossible to indefinitely increase the supply to ordinary burners, multiple-flame burners have been invented, in which two or more ordinary flames are united so that they may impinge upon each other. By an ingenious arrangement for bringing the air into contact with the multiple flames, two excellent types of lamps are obtained, consuming respectively 700 and 1,400 liters per hour, which meet with a rapid demand in Paris, and in many other towns, for lighting wide public thoroughfares, squares, and large open spaces. If, however, it is desired to obtain a flame with a much higher temperature, it is necessary to resort to a special arrangement for heating the air intended for combustion with the gas. The principle of heating the air by means of waste heat escaping with the products of the waste gas—the regenerative principle—was adopted by Mr. F. Siemens, and applied not only to gas burners, but to high temperature stoves. With the Siemens burner on the regenerative principle the following results are obtained: With a consumption of 150 liters per hour, the light of from 1 to 3 carcels; 250 to 300 liters, 6 to 7 carcels; 600 liters, 15 carcels; 800 liters, 20 to 22 carcels; 1,600 liters, 46 to 48 carcels; 2,200 liters, 72 carcels. Unfortunately, the construction of the Siemens Argand lamps is very delicate, and, moreover, they have the disadvantage of being heavy and rather unsightly. In Germany they have been widely adopted; but in France they have met with but little success. The Schulke lamp is made on the same principle; and this appears to be too delicate to come into general use. One of the latest burners of the regenerative class is the Wenham, which has been before the public for some time in England and is now being adopted in France. In point of fact it is merely a very effective improvement on Breittmayer's burner, from which it differs only in its construction; being produced in some elegant styles, which lend themselves perfectly to the decorations of private houses. The No. 2 lamp of this type, with a consumption of 283 liters (10 cubic feet) per hour, has given 126 candles, in a vertical direction without reflectors: horizontally, 50 candles. But the gas employed in the tests had an illuminating power about 20 per cent. higher than that usual in Paris. When experimenting in Paris with a No. 3 lamp in a vertical direction, it showed a consumption of 34.6 liters (1.2 cubic feet) per carcel obtained. The Wenham lamp is constructed to give light in a vertical direction; and by adopting a large reflector, the illuminating power is increased 18 per cent. in a vertical line and 55 per cent. at 80, which is a highly satisfactory result. There are at present five sizes of these lamps. There is also the Delmas hot air burner, in which the batswing flame is completely inclosed in a glass, mounted with a sheet-iron casing, heated by the products of combustion, through which the air passes on its passage downward to feed the flame; and it thus increases the temperature, improves the illuminating power, and produces a beautiful steady light. Mention also may be made of the Siemens radiated heat burner, by means of which the heating of the air is effected simply by the radiation of the metallic parts of the appliance which are in contact with the flame. These burners produce the light of 1 carcel (9.5 candles) with a gas consumption of 70 liters (about 2 cubic feet), and are therefore, from an economical point of view, intermediary between the high power and regenerative burners. This degree of economy can be ascertained by an ingenious arrangement of the air supply in a burner with holes, which has been made in the laboratory of the Wazemmes Gas Company by M. Verl, the engineer, who has invented a very simple burner called the "Lillois," with which the light of 1 carcel is obtained with a consumption of 70 liters. This produces a tulip-shaped flame, and it has a specially constructed glass arrangement on the outside for regulating the combustion. Comparing the above-mentioned burners with each other, we arrive at the following results: The "Lillois" burner consumes 70 liters of gas per carcel; the Siemens ordinary, 70 liters; the Siemens-Breittmayer, 35 to 39 liters; the Wenham, about 35 liters. Taking this into account, and considering that a carcel corresponds with 105 liters of gas consumed in the Bengal form of burner, we see that the economy in gas might, by employing these burners, reach from 33 to 71 per cent. If this is compared with the batswing burner, which produces the light of 1 carcel with a consumption of 120 liters of gas, the economy is greater—varying, according to the type of lamp, from 41 to 85 per cent.

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SYNCHRONIZING CLOCKS.



At the recent meeting of the Institution of Mechanical Engineers, Dublin, Mr. Davey, of Leeds, spoke of synchronizing mechanisms. He had occupied some of his spare time in attempting to synchronize clocks from a standard clock. The problem is similar to the present one, except that it is rough-and-ready, compared to the present one. He had a novel electrical pendulum, to drive a seconds pendulum by electricity. Electrical clocks are notoriously bad timekeepers; on account of variation in the strength of the electrical current, the battery falls off. He had constructed an electric clock having a seconds pendulum, and recording an impulse once a minute. On the pendulum he had a little ratchet wheel, R, having thirty teeth. The pawl was connected with a lever, M, fixed at the top. On the face of the wheel a little pin rotates with the wheel. On the side of the clock case was a contact maker, which closed the circuit by the pin on the ratchet wheel, R, once every minute. The weight was lifted by the electric current, and by its fall gave an impulse to the pendulum. The pendulum was a free swinging pendulum for 59 sec., and the increase of the arc could scarcely be detected.

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COAL TAR AS FUEL FOR STEAM BOILERS.

By JOHN McCRAE, of Dundee.

About three years ago, when the sudden and serious fall took place in the value of the secondary products produced in gas works, many gas managers—ever desirous of doing their very best for their employers—were forced to look around for some better market in which to dispose of the products which had so seriously fallen in value. This was no easy task; and even now it forms very uphill work indeed. A comparatively new market has been created for the disposal of boiled tar at several of the German ports. But the expense and difficulty of loading ships with tar in casks take very much from the saving derived from the new manner of disposal. It occurred to me, therefore, that we must look nearer home for a remedy.

In all gas works of any magnitude, a considerable quantity of fuel must be employed for the purpose of supplying the works with steam for the exhauster engines, chemical apparatus, thawing purposes, etc. Whether this fuel consists of coke or of coal, will not in the least affect or alter my figures. I have no doubt if any manager discovers that he is working more economically by selling the coke and using a cheap small or other coal, he will adopt the cheapest process. In Dundee, where we get a good price for coke, I found, for the purpose of steam fuel, it would be far cheaper to buy small coal costing from 5s. to 5s. 6d. per ton delivered in the works, and dispose of the coke. The question of fuel then lay between coal and tar; and I have experimented somewhat extensively to ascertain the true relative values of the two classes of fuel. For the purpose of this paper, and within the last few days, I made a further examination into the question; and the results arrived at will be those here quoted. The coal we employed was what is known as Stravenhouse small coal, which costs 5s. per ton delivered. The experiment in each case lasted 48 hours. The tar employed was what is known as boiled tar; the naphtha having been previously removed, but the pitch oil left in the tar. The value of this tar in Dundee is about 4s. per ton. The following are the figures:

Coal, 10 tons 16 cwt., at 5s. 2 14 0 Tar, 1,460 gallons (or 9 tons 3 cwt. 160 gallons = 1 ton), at 4s. 1 16 7 ———- Saving per day by using tar. 0 17 5

And this at the longest day, when we are using a mere fraction of steam, as compared with our winter requirements, and consequently the profit is proportionally less than it will be when we are in full work.



And now allow me to direct your attention for a short time to the appliance made use of in accomplishing this tar burning. On the wall is shown a diagram giving in detail the injector known as C. & W. Walker's patent tar sprayer burner; and it is supplied only by that firm. The tar, which has been brought forward to the boilers in a thoroughly liquid state, is discharged from the center of the injector into the furnace of the boiler. Surrounding the center nozzle of the injector is an annular space through which high pressure steam passes, also into the furnace. The meaning of this steam moving along with the tar is to force a draught, as well as to raise the temperature of the tar, and so partially convert the tar into vapor; thereby making the combustion more complete. The flow of the tar is regulated by the very delicate sluices attached to the injectors. These valves consist of elongated cones and plugs, and are constructed not only for the purpose of regulating the flow of tar, but also for removing any obstruction or incrustation which may accumulate in the nozzle. In order to keep the tar in a liquid state (which in the winter time is not an easy matter), a small steam pipe is passed through the center of the tar pipe; but, of course, no steam is discharged among the tar, as the presence of water in the injector prevents its correct working. The steam pipe is simply passed through the tar pipe, and a steam trap attached to its end. In changing from the coal or coke fuel to the tar, little or no difficulty is experienced, and very rarely is a shovelful of any kind of solid material required. The furnace bars have only to be kept covered to prevent the waste of tar and the too rapid ingress of air; and when the furnaces are in full work, and being well and carefully attended to, the tar will be found to have been nearly all consumed before reaching the solid material covering the bars. The action is very much the same as in the paraffin oil lamp. The wick is the medium by which the oil is brought to the point of combustion, where it is developed into light; but the wick remains little injured, although in close proximity to such intense heat. The oil burns, not the wick. In the tar furnace, the tar itself burns, and the tar only.

It will be easily understood that a little experience is necessary to enable the attendant to fully understand the quantity of tar by which complete combustion is to be obtained, and which in no case must be exceeded. The moment one atom of tar is sent into the furnace beyond that which can be thoroughly consumed, you have then the most hideous discharge of black smoke (carbon) which it is difficult to describe, but which can be easily understood, and, I believe, can be seen within a few miles of where we now sit. I should mention that the injectors are fitted on the furnace doors; but the connections are of such a nature that the doors can be opened without disturbing any of the permanent fittings.

And now I have told you that the results detailed in this short paper were those obtained in the Dundee gas works. This is so; but were I to leave the matter here, it might be inferred that I considered similar results might be obtained in any and every gas works. I would not mislead you; and therefore must detain you for a few moments longer in order to show you how my town is different from many others. Dundee is very peculiarly situated in this respect. It is a long distance from any tar distiller's works capable of dealing with the large quantity of tar we have for sale during the winter. A large portion of the value of our tar must, therefore, go to the railway company, to cover the cost of transit between the two points, and so the tar distiller can allow us but a small figure for it at the starting point. Then again, Dundee being far distant from the coal fields, the coal is exceptionally high in price. I quite believe that in many of the west country towns the coal for which we are paying 5s. per ton could be had for 3s.; and the tar for which we are receiving 4s. per ton, they would get not much under the double of this. Therefore, you see, in a place so circumstanced, the figures I have given would be most misleading. Still, I doubt not there are places as badly situated as Dundee; and it is to such places that my remarks are directed. I believe also that, in many towns distant from collieries, the tar might be sold to manufacturers for use in their steam boilers; and such an arrangement would, I think, prove advantageous both to the seller and the user of this liquid fuel.

I think that as much has been said in regard to my subject as is necessary; but permit me to add that I believe there is a future for liquid fuels. I do not say tar, but more concentrated fuels, such as crude naphthas, paraffins, and pitch oil. When you see one of our large steamers taking coal into her bunker, it must have appeared to you that there was great waste of power here. Every ton of coal laid in must require a certain amount of power to carry it; and every ton of coal so laid in reduces the cargo-carrying power to this extent. A few gallons of oil will give you the steam-producing power of a ton of coal; and this is a fact which the owners of non-paying steamships should note. Take our locomotives also. Everything I have said in regard to steamships applies to them; and the comfort to the stokers and the general reduction in labor would be very marked indeed. Of course, it may be argued that if there were such a large demand created for oils for furnaces, the old fashioned law of supply and demand might come into play, and so force up the price of the article for which the increased demand had taken place. But I think this state of matters is rather remote, when we bear in mind the great oil wells only now becoming developed, and the oils from which can be run in bulk direct from the wells into ships, and brought to this country at very low rates.—Journal of Gas Lighting.

* * * * *



WATCH CLEANING AND REPAIRING.

By "OLD FOGY."

Before proceeding with what I consider the best methods in this department of the watch and jewelry business, I will say that I do not, by any means, consider that my way is the best, for although I have been in the business quite a while, yet I find that I learn something new almost every day that I live, and expect to do so, so long as I continue in the business. Be very particular in selecting your tools; about three widths of screwdrivers, and keep them in the best of order, square across the point of blade, and never use a screwdriver too narrow nor too wide for the screw, and in using be careful not to let it slip, and thus mar the plates or bridges of a watch. I also recommend that the handles of these screwdrivers be of different shapes or styles, so as to save time in picking up the one you want (and just here I will say that every device or method that saves time will be of great value to the operator); then have about the same number of tweezers (3), one of good, solid, heavy points, say 1/16 inch wide at the points, for taking down a watch, and handling the heavier parts, and then one a little finer, and one very fine to work in about the train, hairspring, etc., and always keep these tweezers in perfect order at the points, so that whatever you handle, you will not mar or drop the things you are handling. Right in this connection I will say that I cannot find tweezers that suit me. So I make my own, and you can do the same if you will by selecting some nice steel. Then a good assortment of pliers, cutting, flat, and round. In selecting brushes, you will have to be very particular and secure the open and straight bristle brushes, which are also hard to find these latter years. Take all the coarser brushes and hold them on a coarse grindstone, running them whole length, both ways; this takes off the new rough end of the bristles before using first time. Then there are punches, broaches, drills, calipers, countersinks, files, etc., etc. Besides this, I have adopted the plan of making any tool I happen to need for any special purpose, so that by making these at the time I happen to want a tool that I cannot purchase, I have accumulated quite a variety of odd tools; among them are a varied lot of millers, for milling and raising jewels, and deepening the countersink holes for jewel settings and screw heads, also a tool for holding a roller, to set the jewel pin, and one for holding the hair spring collet, and a pair of tweezers for holding jewels while cleaning, etc., etc. As to lathes, I have found that there is a necessity of about two lathes; one a Swiss, light running lathe for cementing any pivot work, and I prefer these because they run much lighter and easier than those heavier American lathes; and yet if confined to but one lathe, I would use a small sized American lathe, with a good assortment of split chucks, particularly those with the smaller sized holes, for holding balance staffs, wheel arbors, etc., which come in use almost everyday, for taking off the burr from the point of a balance pivot, which has come from a collapse of the case; driving the end stones down on the end of pivots, even sometimes to the extent of heading them over inside of the hole jewel. These small size split chucks I have found extremely useful for the last named purpose, and I am not so "sentimental" but that I oftener use these split chucks, even for setting fine balance pivots, rather than take time to cement them; and while I do not advise the use of a split chuck for this purpose in every case, yet with a little experience one can tell when a staff is held so that the new pivot when set will "line" and be true, and of a clear beat or swing. To make a very nice pivot the cementing process is preferable, and yet, for nearly a year, my old No. 1 American lathe was not set up (for reasons I need not take space to explain), and during that time I employed a very skillful workman to do my pivoting, and this man would not think of ever doing a nice job unless he cemented it, and I can assure you that he put in more pivots out of line, and out of true, in the course of those few months, than I had done badly in my life. Speaking of "sentiment," I will say that too many young workmen use the lathe too much, and seem to depend on a fine looking lathe and handsome tools, and spend too much time in using the lathe and in decorating their bench with a fine display. But don't construe this as meaning that one can do nice work with a jack knife and handsaw, for I most certainly believe in a good and substantial set of tools, or I would not have taken so much space in speaking of them. Next, one must have a good bench, wide and of good length: and if no other drawers, a shallow depth drawer, exactly in center of the bench, with no knob in front, but rather a lip running its whole length, underneath. So that wherever you place your hand you can pull it out. This drawer I would have large and roomy (wide and long and extending back as far as the depth of the bench will allow, but shallow, not deep down in), and then partition it off by narrow slats, diagonally across it, running these slats from the extreme near right hand corner to the further and extreme left hand corner, so that as you reach your right hand in to take out a tool, you can grasp it naturally without twisting or cramping your hand. About eight inches below the top of the bench, I would place a skin drawer (the name comes from the practice at watch factories, formerly using sheepskins for the bottoms), which is made with a square frame (say like a picture frame), sliding on slats or a groove, so that it can be drawn out toward the operator, and when so drawn, the elbows will rest on this frame, with the wrists resting on the edge of the top of the bench, thus giving a firm support for both arms and hands, and this frame having stretched across its bottom a skin or canvas, will catch and retain anything that drops or rolls from the bench. This latter drawer I consider almost an indispensable article to doing good and successful work. At the right hand of these two drawers named, running down to floor if need be, there can be a series of drawers for tools and materials. Now with these equipments, and some others, not herein named, such as vise, file block, bench stake or anvil, and a large variety of such tools as will accumulate, I am ready to give you my ideas regarding the cleaning and repairing of watches. First and foremost, do not undertake any job that you have any or considerable doubt but what you can do successfully, and never leave a job worse than you found it; and never mar, cut, or slash any part of a watch. In other words, don't undertake a job that you have doubts as to whether you can do it correctly. One of my old masters told me never to undertake to improve on the maker's work, and this, while not true in every case (particularly cheap watches), yet is a safe rule to go by. Never allow your file, screwdriver, pliers, tweezers, or any tool to deface any part of a watch. I shall speak of this as I proceed. First, be careful and not let the movement swing so as to in any way injure the balance, in taking from case, and if a lever watch, take out the balance the first thing after getting out of case. Now see that the mainspring is let down and then remove the screws from the plates, taking care not to damage or bend any of the pivots as you do this. When all in pieces, before you proceed to clean, examine with a strong glass to see if the rim of any wheel is rubbing or clashing with anything, particularly the center wheel in any full plate American watch, for these wheels are often dragging on the plate or striking the ratch wheel because it is not true, and if examined before cleaning the places where it drags, are a tell-tale of the mischief. Also make any diagnosis of the watch that is needed to discover any errors from wear or accident, and correct them before going further, such as looking to each jewel, pivot, and other parts, and make all necessary repairs before cleaning. I have been in the habit for several years of putting my balance wheel separate from all connections, and trying its freedom in all positions, and if you will try this method, you will be surprised how many you will find that bind or are not perfectly free in all positions, when you give them the very slightest impulse by a twirl of the hand, holding the plate. Then, too, a careful examination of each jewel; you will be surprised how many are either loose in the setting or plate. In regard to cleaning, I use the old method (after trying all ways suggested)—that of chalk (but I use the old lump chalk, for those carpenters' chalk balls are made with some kind of paste that adheres to the plate)—and have this lump of chalk at my right hand, in a perforated bottom box, so that any coarse pieces fall through to the floor, and by rubbing the brush across it and then giving it a slight rap, before applying it to plate, any hard or heavy substance will fall out, and then with light pressure with the brush that is medium soft (and prepared on grindstone as before mentioned, if a new one) brush the plates, with an occasional breathing on the surface, clean the old oil or tarnish, and then peg out each hole many times, until you are sure every hole is clean, by pegging both sides, and then with a soft dust brush dust thoroughly by striking the brush into the holes on both sides. Of course, remove all end stones, and clean out with soft pith, holding the jewels in a pair of hook nose tweezers, mentioned. Should the plates and wheels be very much soiled and oily, a covered dish of alcohol is indispensable, and I have had a glass stopper bottle, with ether, in which to dip the jewels, pallets, and other small pieces, which takes the oil all off, but be sure and clean off with soft pith or pegwood such pieces as you have thus dipped. This ether will carry all loose lint or other things to its bottom, from hairsprings or roller table, and if held but a moment will do effective work, and not loosen shellac.

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