392 CAST [BON, 



Prof. Thurston quotes some results of tests on thick 

 cylinders of cast iron for guns made at Watertown Arsenal. 

 The cylinders. <>f whieh there were nine, were 11 in. external, 

 o-.'Jin. internal diameter, and 22. Un. long. Each cylinder 

 was burst by first tilling it with wax and then forcing in a 

 ram by means of an ordinary testing machine. The results 

 show that the pressure required to burst the cylinders was 

 in all cases slightly lower than that given by any of the 

 usual formulas for thick cylinders. 



210. Model Thick Cylinder Tested by the Author. t 



In 1889 the author made a test of a small thick cylinder 

 under the following circumstances. Soon after the 

 completion of the 100-ton Buckton testing machine for 

 the Whitworth Engineering Laboratory at the Owens 

 College, the ram cylinder of the hydraulic intensifier 

 (shown on Fig. 188) was burst, as it was thought, by the 

 impulsive action of the water from the pressure tank 

 upon the piston. Owing to the sudden stoppage of the 

 column of water coming from the tank, the pressure was 

 greatly above that due to the head alone, and to this is 

 attributed the fracture of the ram cylinder, rather than to 

 any inherent defect in the cylinder itself. The broken 

 cylinder was replaced by a new one of cast steel, with 

 perfectly satisfactory results ; and, at the suggestion of 

 Prof. Osborne Reynolds, under whose direction the tests 

 were carried out, the author cut from the walls of the 

 fractured cylinder a model cylinder, one-eighth the 

 size of the original one, and similar in all important 

 points. An elevation and section of this model are 

 shown on Fig. 189. It will be seen that the top of the 

 cylinder is closed by a screw plug and a packing of 

 leather discs ; the lower end was provided with a stuffing 

 box, packed with leather washers, and allowing the 

 passage of a ram, also one-eighth the size of its full- sized 

 counterpart. In order to reproduce, as far as possible, 

 the conditions obtaining when the large cylinder was burst, 

 the model was placed for testing between the compression 

 plates of the machine, with its upper end quite free and 

 the shoulder at the lower extremity resting on the end 

 of a piece of IJin. steam pipe. 



t See Owens College Calendar for 1890-91. 



