682 
British Association. 
[Ocftober, 
cellulose and the vasculose , they are not transformed direcftly 
into coal. Before being so changed they pass through a 
process of peaty fermentation, which produces ulmic acid. 
It is only in the second place that this ulmic acid is trans- 
formed into coal, mingling with all the coal-forming sub- 
stances produced by the contents of the cells. — The Colliery 
Guardian, being translated from L'Houille. 
VI. THE BRITISH ASSOCIATION FOR THE 
ADVANCEMENT OF SCIENCE. 
Sheffield Meeting, August, 1879. 
(Continued from p. 641.) 
FTER the delivery by Prof. Johnstone Stoney of his 
admirable Address to Section A, an abstract of 
which concluded our report in the “ Monthly Journal 
of Science ” for September, the Report of the Committee — 
consisting of Prof. Sir William Thomson, Prof. Clerk- 
Maxwell, Prof. Tait, Dr. C. W. Siemens, Mr. F. J. Bram- 
well, and Mr. J. T. Bottomley — for commencing Secular 
Experiments upon the Elasticity of Wires, was read by Mr. 
Bottomley. The most important of the experiments con- 
ducted during the past year are those that have been 
made on the elastic properties of very soft iron wire. The 
wire used was drawn for the purpose, and is about No. 20 
B.W.G., its breaking weight, tested in the ordinary way, 
being about 45 lbs. This wire has been suspended in lengths 
of about 20 ft., and broken by weights applied, the breaking 
being performed more or less slowly. During the breaking 
it was found that the wire becomes alternately more or 
less yielding to stress applied. Thus, from weights applied 
gradually, between 28 lbs. and 31 lbs. or 32 lbs., there is 
very little yielding and very little elongation of the wire. 
For equal additions of weight, between 33 lbs. and about 
37 lbs., the elongation is very great. After 37 lbs. have been 
put on the wire seems to set stiff again, till a weight of 
about 40 lbs. has been applied ; then there is rapid running 
down till 45 lbs. has been reached. The wire then becomes 
stiff again, and often remains so till it breaks. 
