UNIFICATION OF METHODS IN TESTING MATERIALS. LY. 
In reply to Mr. Sinclair on the tests of pipes and boilers by 
means of hydraulic pressure, the author recommended the test to 
be continued up to the working loads, as he considered that the 
practice of testing a boiler to double the working load might pro- 
duce permanent strains; but he saw no objection to one and a 
half times the working load if ordinary care is used in making the 
test, or even a higher pressure if care is taken to avoid overstrain- 
ing. As the paper was not intended to deal with boiler tests, the 
remarks should have been restricted to pipes. 
In regard to Mr. Selman’s remarks, the author was astonished 
at the statement referring to the practice in England ten years 
ago. The object of the International Union for the Unification 
of Tests had been sufficiently explained in the paper, but accord- 
ing to Mr. Selman there would appear to be no necessity for such 
a society, or of the various other societies in America and France, 
he appeared to have misunderstood the paper in various particulars. 
In regard to his remarks on the elastic limits and yield points, it 
was incorrect to say that no reference had been made to the 
apparent elastic limit. There is also no justification for the state- 
ment in which he implied that the author considered the yield 
point a criterion of the elastic properties of the material. Surely 
no one reading the paper carefully could draw such an extraor- 
dinary conclusion as to the meaning of the author. The state- 
ment as to whether the elastic limit is determinate or not should 
have been explained more fully, as it was not clear enough for the 
author to reply to. The standardizing limit proposed by Mr. 
Selman appeared to be decidedly inferior to the relative limit 
proposed by Professor Johnson. In regard to his reference to 
Professor Tetmaier’s tests, the author wished merely to state that 
Professor Tetmaier was acknowledged to be one of the most. 
eminent authorities on the testing of materials, and had a world- 
wide reputation. 
