4 GWYTHER, Modes of rupture of a lieimspJieyical shell. 



Specimens 2. and 2a. had the following dimensions : — 



internal diameter, 9 inches. 



external diameter, i r inches. 



height, 4"2 5 inches, 

 and 2a. was reinforced at the base with two rings of 

 one-sixteenth inch diameter wire. 



2. Longitudinal cracks first appeared under a load of 

 2"6 tons, commencing at the base and spreading 

 upwards, but did not reach the top, being higher 

 on the outside than the inside. The latitudinal 

 rupture took place under the load of 46 tons and 

 was irregular, the vertical breaking stress in this 

 case being 328 lbs. per sq. inch. On removing 

 the specimen from the machine the lower portion 

 was found to be in sections, but the top held 

 together. 

 2a. Longitudinal cracks appeared under a load of 

 725 tons and spread from the top downwards as 

 the load increased. At the load of iO'68 tons the 

 specimen broke latitudinally, the top collapsed, 

 and, falling inwards, broke a part of the base to 

 the level of the reinforcement, the longitudinal 

 cracks not having reached the reinforcement. 

 The breaking stress was in this case 76r4lbs. per 

 sq. inch. The load was not removed sufficiently 

 quickly, and the injury to the specimen was 

 partly due to testing it in a horizontal machine. 

 The latitudinal crack was irregular but roughly 

 normal to the surface. 



The dimensions of specimens 3. and 3a. were as follows : — 



internal diameter, 6 inches, 



external diameter, 8 inches, 



height, 275 inches, 

 and 3a. was reinforced at the base. 



