MECHANICS AND USEFUL ARTS. 97 



Weaver's Breech-loading Fire-arms. In an improvement patented October, 

 1855, by H. B. "Weaver, of Connecticut, there is a movable chamber at the 

 breech of the gun for receiving the cartridge, the chamber being hinged so as 

 to open up, laterally, like the lid of a snuff-box. The opening and closing of 

 the chamber is effected by means of a trigger guard lever located underneath 

 the stock, the same as in most of the breech-loading fire-arms. There is also 

 a very ingenious self-acting contrivance for putting the percussion caps upon 

 the nipple. By the act of opening the cartridge chamber the hammer is 

 cocked and a cap placed upon the nipple ; all that remains to be done is to 

 slip the charge into the chamber and close the same, when the piece is ready 

 for instant discharge. Scientific American. 



Mr. Andrew Smith, of England, has recently exhibited a model of a gun, 

 arranged for the purpose of employing oxygen and hydrogen gases, produced 

 from the decomposition of water by galvanic electricity, the projectile force 

 from the combustion of which is nearly double that of gunpowder. The gen- 

 eration of the electric gases takes place in a chamber beneath, the reiterating 

 propelling force being admitted intermittently behind each ball by means of 

 a valve, the whole being contained in the compass of the carriage of an ordin- 

 ary ship's gun, or battering cannon, and but little exceeding them in weight. 



The guns intended for the new steam frigate Merrimac, recently launched 

 at the Charleston Navy Yard, are of peculiar construction, being very large at 

 the breech, and beginning to taper abruptly near the center, terminate small 

 at the muzzle. They are provided with an elevating screw, sufficient to ele- 

 vate 9 45', and depress 7 30'. The carriages, also, are of a new model, 

 having no after trucks. The guns thus provided will be more steady upon, 

 the deck, and not so h'able to break from their breechings at sea, while in 

 firing the recoil will be sufficient to throw them back. 



Improvement in Percussion Caps. M. Neron, of Paris, at a recent meeting 

 of the Institution of Civil Engineers of Great Britain, exhibited an ingenious 

 mode of placing detonating caps on the nipple of a rifle or a musket. The 

 apparatus consisted of a tube containing twenty-two caps, placed parallel with 

 and close beside the barrel, being partially inserted in the stock, and so ar- 

 ranged that while the near end was attached by a pin to the hammer, the 

 further extremity was free to travel in a slot. Its action was very simple 

 the tube being filled with caps from a reservoir, several of which would oc- 

 cupy but a very small space, the end cover was turned down. On drawing 

 the hammer to half-cock, the tube was drawn forward until a cap was brought 

 over the nipple, and at full-cock the cap was pressed down upon it. After 

 firing, if any portion of the copper remained attached to the cap, it was re- 

 moved by a small picker preceding the tube, on its being again brought for 

 ward to repeat the operation. It was evident that by this simple and cheap 

 addition to any fire-arm, much time must be saved in loading, and a great 

 waste of caps must be avoided, while about twenty-five per cent, of copper 

 was saved in making the caps and they were kept dry in the reservoir in- 

 stead of being exposed to damp and running the risk of not exploding, as had 

 occurred frequently in action on recent occasions in the Crimea. 



Improved Artillery Vent. A new artillery vent has recently been tried at 



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