i6 Stromeyer, Explosions of Slea?n Pipes. 



along a pipe and meeting with an obstruction. To repro- 

 duce this condition, my assistant, Mr. Baron, has prepared 

 a pipe with water pockets, on breaking off the end and 

 admitting air behind the lowest plug of water the pipe is 

 shattered at the first water pocket. This experiment 

 also clearly shews that the pressure caused by the impact 

 acts in all directions. 



At the conclusion of this paper, I intend to reproduce 

 experimentally the conditions set up in the cases illustrated 

 in Fig. I. A glass tube bent like an L is connected at 

 its top end with a flask in which steam is generated. 

 This represents the boilers at work, the other end is 

 closed with an India-rubber stopper, representing the stop 

 valve of the boiler about to be connected to the main 

 steam pipe. The customary drain cock is attached here. 

 As soon as steam is get up and the water in the pipe 

 lowered, a violent commotion is set up, which is accom- 

 panied by water-hammer blows, and these would drive 

 out the India-rubber stopper if air cushions had not 

 been left in the water. Reports on accidents of this class 

 are very numerous. 



In order to ascertain the stresses set up in the walls 

 of steam pipes subjected to water-hammer action, it would 

 be necessary to retrace our steps and to repeat the above 

 investigation, not for the elastic, but for the plastic, 

 condition of materials ; and, as we know as yet little 

 about plastic stresses, we should even have to discuss the 

 very probable possibility of these stresses being functions 

 of the durations of blows ; when this has been done, and 

 experiments similar to those of Dr. Hopkinson have 

 been repeated, we shall be in a position to decide what 

 influence the various materials of which steam-pipes are 

 made have on the stresses produced by water-hammers. 

 To go into these matters, however, would enlarge this 

 subject too much. 



