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100 lbs. was borne with ease. The remainder of the experi- 

 ments were made with short pieces of pipe varying from one to 

 three feet in length. 



A piece of the same pipe was subjected to the full test ; it 

 bore 266 lbs., and burst at 272 lbs. 



Another piece of the same diameter internally, with one and 

 five sixteenths external diameter, from a different factory, bore 

 300 lbs., and burst at 320. 



Pipe of seven eighths of an inch internal diameter, and one 

 and one eighth external diameter, stood a pressure of 280 lbs., 

 and burst at 304 lbs. 



Pipe of five eighths internal, and one and one thirty-second of 

 an inch external diameter, stood 320 lbs., and burst at 360 lbs. 

 This is the size used in Boston for the Cochituate Water, and is 

 there subjected to a pressure of not more than 60 lbs. 



Pipe of one half an inch internal, and five eighths of an inch 

 external diameter, bore 234 lbs., and burst at 240 lbs. 



Pipe of the same diameter but of another manufacture, 

 intended for an ordinary pressure of 35 lbs., stood 360 lbs., and 

 then burst. 



Pipe of quarter of an inch internal, and five eighths of an 

 inch external diameter, stood 720 lbs., and burst at 760. This is 

 a stout pipe, used in the shops for effervescing soda water, and 

 generally subjected to a pressure of about 200 lbs. 



Dr. A. A. Hayes asked at what temperature the experiments 

 were made, as the power of cohesion would vary with the tem- 

 perature. 



Dr. Storer replied, at the common temperature of the Cochit- 

 uate Water. 



Prof. Wm. B. Rogers asked if these pipes were of recent 

 manufacture. He had made experiments upon the cohesive 

 properties of Gutta Percha and had found that a very remarkable 

 molecular change takes place, after some length of time, in the 

 material, so that it readily breaks up and becomes utterly worth- 

 less in that condition. 



Mr. Charles Stodder stated that the material which had been 

 in the market at different times was of very different qualities, 

 and that the crude article itself, was extensively adulterated by 



