80 ANNUAL OF SCIENTIFIC DISCOVERY. 



a liberating chain attached to the roll on to an iron carriage, which 

 conveys the pile to the rolls. The carriage travels upon a line of 

 rails let into the ground ; and close in front of the roll frame is a 

 small incline upon the railway, which lifts up the front of the car- 

 riage at the moment of its arrival at the rolls, and enables it to 

 deliver the pile upon the fore plate. As the plate passes through the 

 rolls it is received on the other side upon a roller frame, which is set 

 at a considerable inclination toward the rolls, so that the tendency 

 of the plate is to return. The rolls are then reversed ; and the plate 

 which was pressing against them passes back through, and is received 

 upon the carriage ; and again the operation is repeated, until the 

 ten inches thickness is reduced to four and one-half inches. The 

 plate is then lifted off the carriage by a crane, and deposited 

 upon a massive cast-iron straightening bed. Here an iron cylinder 

 weighing nine tons is rolled over ifc to and fro, being pinched along 

 by hand levers, until the curvature which the plate has acquired in 

 the roUing is entirely removed. As soon as the plate is sufficiently 

 cool, it is lifted off the straightening bed by another crane, and laid 

 upon a planing machine, where the final operation of planing its 

 sides and ends is completed. 



RECENT APPLICATIONS OF SCIENCE CONTRIBUTING TO THE EFFI- 

 CIENCY AND WELFARE OF MILITARY FORCES. 



The following are abstracts of points noticed in a lecture on the 

 above subject, recently delivered by Mr. Abel, Director of the Chem- 

 ical Establishment of the British War Department : 



A subject of importance in connection with the repeated firing of 

 a rifled- gun relates to the solid substances, or residue, obtained on the 

 explosion of powder, particularly in a confined space, such as the 

 barrel of a gun. In the old smooth-bore cannon or small-arms this 

 residue was carried away, to a very great extent, on the discharge of 

 the piece, by the sudden rush of gas, so that a cannon could easily be 

 kept clean by the employment of a mop or sponge after the discharge. 



But in the case of the rifled gun with expanding projectile, which 

 may be regarded as a close chamber for a short interval after the dis- 

 charge (as the projectile, when acted upon by the exploded powder, 

 exactly fits the bore of the gun), this escape of the gas is, compara- 

 tively speaking, greatly retarded, so that the residue is no longer 

 held in suspension and swept out of the gun to any important extent. 

 It is, moreover, powerfully compressed by the force of the discharge ; 

 consequently we find large masses of residue accumulating in the 

 barrel. Its quantity is, moreover, greatly increased by the charred 

 remains of the cartridge-bag, which, in the smooth-bore gun, is almost 

 entirely expelled on the discharge. It has therefore been a matter 

 of great importance to promote the removal of this residue, so that 

 each discharge should at any rate carry away the dirt or residue left 

 by the preceding one. In cannon this is very readily effected by 

 the employment of a wad of hemp or some similar material thor- 

 oughly saturated with fatty matter, or by the use of a cake consisting 

 of the lubricating material only. Sir W. Armstrong places a lubri- 

 cating wad between the powder and the projectile ; Mr. Whitworth 



