involved in the Construction of Artillery. 311 



guns have been pointed out, and the conditions of their injury or 

 destruction thereby shown ; the precautions necessary in firing 

 red-hot shot, &c., indicated ; some ancient mistakes rectified ; and 

 tlie comparative values of the four great materials for ordnance, 

 in respect to distortion, ascertained. 



15^. The long-vexed and confused question, as to the presumed deterio- 

 ration of wrought-iron at common temperatures by vibration, has 

 been cleared up, in a great degree, by the application to it of 

 the general law of crystallization ; the causes of the changes of 

 fracture, under the stroke of shot, pointed out for the first time ; 

 with a comparison of the effects of the stroke of shot upon the 

 four great materials of ordnance. 



16°. The relations of the rapidity of the exploding agent to the material 

 of the gun have been discussed, and some more precise views 

 advanced of the nature and conditions of wear, and enlargement 

 of vent and bore in guns. 



17°. The efiects of position, with respect to the axis of the gun, upon 

 the ultimate resistance of the metallic filament, has been investi- 

 gated in a new light, and its relations to, — 



18°. The efiects, on the resistance of the gun, of the position of its trun- 

 nions, or other fulcra of recoil, and of the simultaneous action of 

 forces of extension and compression within its mass. 



19°. The doctrines of authors on Physics, as to the relations between 

 the force of contraction or expansion by heat, and corresponding 

 mechanical efl'ect in metals, has been placed in a new light, and, it 

 is hoped, with some advance of truth. 



20°. Some new views as to the nature and efiV-cts of annealing, and the 

 relations between the temperature at which it takes place, and 

 that of fusion, and of the work done by rupture, on hard or un- 

 annealed and on soft or annealed metals, have been adduced. 



21°. The relative advantages, and the objections which may be urged 

 against the adoption of wrought-iron guns, and especially of that 

 peculiar construction proposed, have been discussed, it is hoped, 

 in a true and impartial spirit. 



2 s2 



