ANNUAL OF SCIENTIFIC DISCOVERY. 



MOVABLE TAEGET. 



The following ingenious contrivance has been adopted in the experimental 

 gunnery ships of the British Navy : It consists of a circular target, fitted on a 

 ball and socket support, and capable of being moved in ah 1 directions, but so 

 arranged that upon a string being pulled its movements are suddenly arrested. 

 The target is placed at one end of the deck, and a wooden gun pointed towards 

 it at the other. The manual exercise is performed at tin's gun as at any other. 

 "When the captain of the gun comes to the final operation of pointing, he seizes 

 the end of a long string attached to the apparatus which arrests the target, and 

 which is passed through a ring near the screw fixing the lock to the gun : and 

 as soon as, in his estimation, the gun bears directly on the bull's-eye of the 

 target, he pulls this string, as he would the lock -lanyard ; and in one instant 

 the target becomes stationary. The officer superintending the exercise has 

 now the means of examining the position of the gun, and of ascertaining 

 whether or not it has been well pointed. This appears to form an admirable 

 introduction to the real practice with shot. 



This wooden gun, it may be mentioned, is fitted with a small eye-hole right 

 through its length, by which an object may be looked at along the axis of 

 the bore, and the difference of pointing by the line of metal and by a gun dis- 

 parted is made at once apparent. This device was first suggested by Sir 

 Samuel Pechell, who remarks, that "in the first place it is necessary to con- 

 vince sailors practically that the thing you wish to teach them is absolutely 

 necessary." Until, therefore, " they are shown why the line of metal will not do 

 for a point blank shot so well as a line produced by disparting, and which shall 

 be parallel to the axis of the bore, they will not care whether they use a sight 

 or not." 



IMPROVEMENTS IN THE MANUFACTUEE OF PAPER. 



Paper from Refuse Tanned Leather. Lazare Ochs, of Belgium, has obtained 

 a patent for making paper from the cuttings, waste leather, and scraps of 

 tanned leather. The manufacture of paper from leather is an old story, as an 

 American patent was obtained for such paper many years since ; but 

 M. Ochs' method of treating his leather to take out the tanning is worthy of 

 attention for its simplicity. The scraps of tanned leather are placed in sieves 

 on the ends of arms or spokes on a wheel, and are made to revolve in a 

 stream of water, which operation, when continued long enough, washes out 

 the tannin from the leather. After this about 20 per cent, of old hemp rope 

 is mixed with the scraps, and the whole is cut up and reduced to pulp, from 

 which the paper is made. A very strong coarse wrapping paper is made in 

 this manner. 



Paper from the Bark of the Cotton Stalk. Experiments have been recently 

 made to develop a hemp, suitable for paper manufacture, from the bark of 

 the cotton stalk, with a fair prospect of success. The best period for pre- 

 paring this cotton hemp is as soon as practicable after the picking of cotton 

 has been finished. The plants should then be pulled up and dew-rotted like 



