Miscellaneous Intelligence. 445 
5. On Gutta Percha tubes, (Proc. Bost. Soc. Nat. Hist., v, 268. )— 
Dr. H. R. Stoner reported the results of some recent experiments 
upon the cohesive properties of different sizes of Gutta Percha pipe, 
made in connection with Mr. Charles Stodder. 
The first trial was with one thousand feet of a pipe, of one inch in- 
A piece of the same pipe was subjected to the full test; it bore 266 
Ibs., and burst at 272 Ibs. 
Another piece of the same diameter internally, with one and five- 
sixteenths external diameter, from a different factory, bore 300 |bs., 
and burst at $20 Ibs. . 
Pipe of seven-eighths of an inch internal diameter, and one and one- 
aon external diameter, stood a pressure of 280 lbs., and burst at 
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 
e size used in Boston for the Cochituate Water, and is there sub- 
jected to a pressure of not more than 60 lbs. 
ipe of one-half an inch internal, and five-eighths of an inch exter- 
hal diameter, bore 234 |bs., and burst at 240 lbs, 
ipe of the same diameter but of another manufacture, intended for 
an ordinary pressure of 35 Ibs., stood 360 Ibs., and then burst. 
Pipe of quarter of an inch internal, and five-eighths of an inch ex- 
ternal diameter, stood 720 Ibs., 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 Ibs. 
r. A. A. Hayes asked at what temperature the experiments were 
made, as the power of cohesion would vary with the temperature. 
Dr. Storer replied, at the common temperature of the Cochituate 
ater, 
_ Prof. Wm. B. Rogers asked if these pipes were of recent manufac- 
ture. He had made experiments upon the cohesive properties of Gutta 
Percha and had found that a very remarkable molecular change takes 
place in the material after some length eat es that it readily 
reaks up and becomes utterly worthless in that condition. : 
Mr. Chenes Stodder acd shee 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 the natives before 
exportation. When first introduced here and into England, much bad 
material was obtained. Some samples were found to be acid, and 
lime was recommended for its neutralization. This remedy however 
Soon became an abuse, for lime and oxyd of zinc were at one time ex- 
tensively used for its adulteration, no less than fifty per cent of lime 
being often introduced. Mr. Stodder has specimens of the pure gum, 
Manufactured into different articles several years since, now in good 
Condition. 
