406 THE SCIENTIFIC PAPERS OF 



the outside was at its full temperature, layer after layer of metal 

 would be formed at a gradually reducing temperature, all of which 

 would be, under those conditions, in a state of perfect rest and 

 equilibrium. ' After some time, perhaps an hour, there would be 

 au outside temperature of say 600 Cent., and at the inside 100 

 Cent. The coil being taken out of the furnace and allowed to 

 cool, the result would naturally be that in each layer a tension 

 would be formed proportionate to the relative temperatures. The 

 contraction on the outer surface would be very great, and it would 

 act as shrinkage upon the rest. The shrinkage of the surrounding 

 layers would be less and less, and the total result would be a 

 tension which might be represented by a diagram showing a 

 maximum positive strain near the outside of the gun, and a 

 maximum negative strain in the metal nearest the inside of the 

 gun, the neutral axis being somewhere midway between the two. 

 The explosive action of gunpowder upon such a tube would cause 

 the internal negative pressure to be transferred into a positive 

 pressure ; it would act on the larger diameter in a less and lees 

 degree ; and, when the full pressure was acting, there would be a 

 field of compression which might possibly be represented by a 

 diagram showing equal positive tension throughout the mass. In 

 that way it would be possible to obtain, by means of a single ring, 

 all the advantages which the author claimed for his wire system, 

 with the additional advantage of having strength in all directions, 

 it being unnecessary to amplify the gun after all the required 

 strength was obtained, by two or three times the amount of dead 

 weight. He believed that an inner tube would always be 

 necessary ; but it should not be a resisting tube. A tube of hard 

 metal surrounded by comparatively weak metal, appeared to him 

 to be a great mistake, which was shared both by the Woolwich 

 system and by the plan proposed by the author. The inner tube 

 should be of metal that accommodated itself entirely to the outer 

 tube and to the necessities of the gun. It should be extra mild 

 steel, which would expand or extend 30 per cent, without break in 

 its continuity. Any hard metal, such as hard steel or cast iron, 

 would be subject to such action and reaction as to bring about its 

 final destruction ; whereas a lining of metal that Avas like putty in 

 its constitution, coupled with great strength, was, in his opinion, 

 the proper lining of a gun surrounded, not by a series of rings, but 



