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Commencing in the town of Rosendale, there rises up from the valley of the Rondout, and from beneath its bed, a white and rose tinted quartz rock, sometimes very coarse, at others fine grained, and again, in other layers, of a conglomerate character. Locally, it is known as the Esopus millstone grit. It increases in thickness, and gradually ascends, progressing southwards until, in the town of Rochester, it is from 300 to 500 feet thick, and 500 to 600 feet above the level of the valley. It maintains this height, unbroken by a fault or cross valley, to the Delaware water gap, in New Jersey. The anatomy of its layers appears to be these: a, conglomerate, reposing upon the block slate; b, coarse gray layers, succeeding; c, drab colored layers, often shaly in character; C, white sandstone; d, white pebbles, cemented together; e, white sandstone; f, red colored layers, sometimes shaly, more often sandstone (fossiliferous, rain drops and wave marked). At the base of the mountain are seen the limestone series, which succeed the Shawangunk, sometimes rising into hills, but usually underlaying the valleys of the Rondout and Brasherkill and Neversink rivers.

This Shawangunk grit is divided up into smaller masses, usually having well defined angles, by a system of fissures running in lines coincident with the trend of the mountain, and cutting at right angles across it. It is in these fissures that lead, copper and iron pyrites are found. Where the fissure is wide enough to hold an amount of mineral of sufficient economical value to work, there we have a mine, as at Ellenville, Wurtsboro', and the newly discovered vein of the Messrs. Guamaers. This latter is one of these fissures, from two and a half to five feet wide, filled in with clay, rubbish, or broken rock and galena. Its course is

up

and down the mountain, about S. 70° E., and N. 70° W. It is nearly perpendicular, and at this date a shaft has been sunk upon it about thirty feet. Uniformly it bears galena, very compact, of fine grain, and steel gray in color; bi-sulphate of copper, zinc and iron are found with it, but sparingly, Its location is. about midway of the mountain, up and down, a few hundred feet from the Erie railroad, above it; and geologically, in the white and gray sandstone layers, immediately below the red layers.

The regular subject of the evening, .“ Implements of Modern Warfare,was then 'taken up..

Mr. Schoonmaker explained his conceptions of a torpedo to float at any required depth in the water of a harbor or river: the arrangement of a mirror with a graduated line across it so as to tell by inspection when the vessel of the enemy is exactly over the torpedoes, when they are to be discharged by galvanism, with modifications for use and fall of tubes.

Prof. Seely remarked that very quick powder might attain a higher heat during an explosion of a gun than the 8,400 mentioned by Mr. Wiard, and slow powder less, according to space and previous temperature and condition of the material of the gun.

Mr. Wiard described some recent experiments as to the non-conducting peculiarity of water. He placed a vessel with copper bottom and clay sides on the top of a very hot stove, the vessel filled with lumps of ice and flooded with cold water. After the vessel had remained there one and a half hours, and after a common tin vessel of cold water had boiled, and was constantly boiling hot, in the same exposure, he found that scarcely any of the ice had melted. He then applied heat to the top of a vessel similarly arranged with copper top and clay sides, and filled with ice lumps and water, and found that it melted very soon; all which he explained on the principle that water is at its minimum density at 40° Fahrenheit, and that when the ice touched the bottom of the vessel on the stove it became denser and denser as it warmed towards. 40°, and remained a non-conductor, the heaviest at the bottom. But when the heat was applied to the top of the ice, then it melted into water, and as this water warmed towards 40° it condensed and sank, carrying down heat to the ice below until it was all melted and raised to about 60° of temperature. He concluded that water conducted heat only by circulation, and not by transmission; hence, to melt ice, apply the heat to the top or sides of a vessel.

FIELD ARTILLERY. Mr. Norman Wiard. The United States field artillery carriage, of the present day, of which more than twelve hundred have been ordered since the rebellion commenced, is, in most essential particulars, the French system of Gribeauval, of 1765. A slight improvement was adopted in 1827, viz., in making the trail single.

The resistless force of public opinion caused some attention to be given to rifled field guns at the beginning of the rebellion; but this was, however, mainly due to the attention given to the subject by that arch traitor, Jefferson Davis, when in the cabinet of the United States, perhaps for the purpose of entailing the expense of experiments on the government, in order to use the knowledge so obtained, at a later time, to enable him to subvert the very government affording him such facilities. But the new principle was so imperfectly applied that rifled guns 'came very near being discarded altogether.

The chief errors in practice, however, resulted from retaining the old standard carriages, designed for smooth bore guns; using projectiles of double the weight for the same weight of gun, for the rifle güns; in adopting calibers that were too large, and in using bronze, a material that has been found, after careful experiment, not to possess the required endurance. A six-pounder smooth bore gun was originally designed to deliver a projectile of such a size as would allow a proper number to be carried in one limber ammunition chest, and such shells burst into a sufficient number of pieces to be very destructive within moderate ranges; but when rifled guns came into service, the smallest projectile at first proposed was one weighing fourteen' pounds, for the James' caliber of 3.80. This caliber was adopted, because U. S. six-pounder smooth bore damaged bronze guns could be reamed out to that uniform size, and rified. The weight of this carriage and gun had been arranged for a projectile to weigh six pounds. When the heavier projectiles came to be fired from them, the recoil was found to be so great as 'not only to materially increase the labor of the gunners, and affect the precision of aim, but it had the effect to destroy the carriages. It was also found that the guns soon became enlarged in the bore, which was accounted for by the increased strain upon them. "It was, however, chiefly due to the longer time the surface of the bore was exposed to the heat of the powder. First, the heat expanded the inner metal, dis

tending or stretching the outside ductile metal; then, when the gun was cooled, the inner metal was distended slightly beyond its elasticity, and it was enlarged. This effect will always be more apparent in a bronze than in a wrought iron or steel gun, and it destroys a bronze rifle gun after a few rounds, and this effect is produced much sooner where the twist is very quick, as in the Dahlgren navy bronze rifle howitzers, which have one turn in five feet, or more than twice as much as is proper. ' After the "James' gun," the next field rifle gun officially adopted was the three inch wrought iron gun. In this model the caliber was still too large, as but forty rounds can be carried in"

"one ammunition chest, and the gun is much too long for rapidity of working and accuracy of aim, and is too light for the weight of projectile, it 'having only about eighty pounds of 'metal in the gun for one pound of shot. The best proportion is to have the gun about 100 times as heavy as the powder and shot, and the gun and carriage about 300 times that weight." The three inch' gun was mounted on the same carriage as the old six-pounder smooth 'bore' gun, and its' recoil was found to be so severe that the carriage was destroyed. Hon. P. H. Watson, the able and intelligent Assistant Secretary of War, once informed me that he had received a great many reports of broken carriages, and I saw about thirty broken or bent axles after the second battle of Bull Run, all of them 3-inch guns or 10-pounder Parrotts. I saw, also, at the Washington arsenal, several axles injured by proving 12 and 24-pounder James' guns on their carriages. These guns were afterward dismounted and fired while lying on the ground, when they recoiled from twenty-three to thirty-four feet. When it is considered that if the gun and shot were of the same weight, the gun would be projected as far as the shot, it will be seen how important a part "recoil” plays in the delivery of the shot, and of the accuracy

A gun carriage wheel does not roll back as far as the gun recoils; it merely slips a part of the distance, and, as the wheels are the last part of the carriage to recoil, the consequence is, many of the axles are bent, broken, or twisted out and away from their fastening under the cheeks and trail, where the fastening is insufficient, it being on the top of the axle only, which is bent or broken by the resistance to recoil by the heavy wheels.

When the rebellion was first inaugurated, the authorities of the State of New York caused all the gun carriages belonging to the State to be examined for the purpose of putting them in repair. These carriages had not been in service, but had stood unused for years in the arsenals. I was present when some of them were examined, and it was decided that all would require repairs to the wheels; many of the spokes would have to be taken out, wrapped with canvas and re-driven, and that all the tires would have to be cut, welded, and re-set. It was estimated this would cost $40 for each of the carriages belonging to the State. The wheel I have designed and adopted for all my field artillery carriages, hereinafter shown, resulted from the suggestions I received at that time.

I have, however, found it necessary to make the following improvements on my original carriages, viz:

Improved sights and means of adjusting, a number of additional spare articles for repairs, among which are two spare hubs and plates, and chains

and range.

attached to the battery wagon to carry them; also, parts of wheels, bolts, etc., an anvil block, an improved grindstone frame, and a maul.

I now propose to furnish a 12-pounder howitzer in place of my original 12-pounder rifle, thus requiring but one size of carriage for my 12-pounder smooth bore and 6-pounder rifle field gun; also to fix the implements on the top of the trail, where they are not liable to be lost or injured in passing over bad roads.

An improved elevating screw adjustment, to avoid injury to the gun by pounding on the head of the screw in traveling, and to avoid the projection of the screw below the trail where it was liable to strike stumps or other obstacles when passing over newly cut roads; and relieving much of the difficulty found in moving over wet and muddy roads with the present carriages.

An improved canister, better adapted to rifled guns.

Improvements in the construction of the wheel, by which repairs are facilitated, and an improved manner of mounting the trunnions on the gun.

One of the objections heretofore made to rifled light artillery has been that canister could not be made effective, as the expansion of the case containing the balls filled the grooves and caused the canister and contents to revolve about its own axis as it left the muzzle of the gun, with so high a velocity, that centrifugal force scattered the shot in every direction except

the one in which it was aimed; many of the shot would strike the ground immediately in front of the gun, some would be thrown to the extreme right, some to the left, and some to and beyond the object.

An effective canister, such as is hereinafter described, will, by its adoption into service and use, enable rifled guns to recover their deserved popularity,

The Wiard canister is specially adapted for rifled guns, but is equally effective in smooth-bore guns; it is somewhat different from the ordinary canister, having a cast iron case in sections, the main object attained being the passage of the case from the gun without expansion into the rifle grooves. Each ring or section is rounded on its edge, so as to pass over the grooves.

The opposite figure is a side view partly in section, and a cross section on the line SS. of a canister constructed according to my invention. A and B are the end castings, and CC, etc., are intermediate castings forming a completely inclosing case for the shot D. A wire E connects the front plate A with the rear plate B through the aid of the hook bolt E!, and tightening nut e. Each of the rings, or intermediate castings, CC, is flanged at its forward edge, and provided with three points ccc at its rear edge. These narrow surfaces may

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be readily reduced by a file, or any other suitable tool, so as to make the form practically perfect, and insure that the canister, when tightly drawn together, shall be straight with very little labor in the fitting. When this canister is fired from a rifled gun, the castings ABC ride upon the lands

alone, and the whole behaves exactly as if the gun were a smooth bore. The exterior of ABC may be finished or covered with

cloth or paper to induce a gentle effect on the gun, and the number of the rings C interposed between A and B may be increased or diminished, according to the strength of the gun. All the castings AB and CC are rounded on their exteriors, so as to correspond in form with a portion of a sphere or spheroid. This renders it impossible for the edge of any casting to come in contact with the inner surface of the gun, and abrade it under any

circumstances.

GG are holes in the rear casting A, which allow the gases to enter and permeate among the balls D, while the canister is moving along the bore. As soon as, or before, the canister escapes from the muzzle, the hook bolt or wire breaks, and the canister is expanded lengthwise by the tension of the gas thus admitted, through the holes GG

at the rear end, the 'do

We hook bolt El breaking

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The 6-pounder rifled gun.

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