396 
are always dissimilarities. Taking the 
psychical view—the only view which we 
really do at present take—in the living be- 
ing there is always some individuality, 
something different from any other living 
being, and full prediction in the physical 
sense, and by physical methods isimpossible. 
If this be true, the loom of Nature is weav- 
ing a pattern with no mere geometrical de- 
sign. The threads of life, coming in we 
know not where, now twining together, now 
dividing, are weaving patterns of their own, 
ever increasing in intricacy, ever gaining 
in beauty. J H. Poyntine. 
MASON COLLEGE, BIRMINGHAM. 
THE WORK OF THE INTERNATIONAL ASSO- 
CIATION FOR TESTING MATERIALS.* 
Prior to the year 1800 little was known 
of the properties of the materials of con- 
struction. Gallileo had shown in 1638 that 
the strength of a rectangular beam varied 
with the square of its depth ; Hooke in 1678 
had announced the law that the stretch of 
a spring was proportional to the stress upon 
it ; various authors had discussed the forms 
of beams of uniform strength, and Euler, in 
1744, had enunciated his formula for the re- 
sistance of columns under compression. The- 
ory was far in advance of practice, for experi- 
ments had been so few and so imperfect that 
the elastic limit was scarcely recognized. 
During the years from 1800 to 1850 great 
progress was made in the theory of elas- 
ticity, and a slow growth took place in 
knowledge of the properties of materials 
under stress. The introduction of railways 
and the consequent necessity of providing 
a firm roadbed and safe bridge structures 
gave a powerful stimulus to the investiga- 
tion of metals, in order that ample security 
might be afforded with the greatest degree 
of economy. The methods of testing were, 
* An address by the Chairman of the American Sec- 
tion of the Association, at the second annual meeting 
held in Pittsburg, Pa., August 15-16, 1899. 
SCIENCE. 
[N.S. Voz. X. No. 247. 
however, so imperfect that progress was 
slow, and, with the exception of the classic 
researches of Hodgskinson, the work of this 
period was mostly of value as a preparation 
for that of the future. 
After 1850 large testing machines for 
special purposes began to be built, elonga- 
tion and ductility began to be carefully 
studied, and soon after 1870, it was recog- 
nized by many manufacturers that physical 
tests of metals were imperatively necessary 
in order to secure uniformity of product. 
As these tests were multiplied and the 
records subjected to investigation, the 
knowledge was gained that the strength of 
a specimen depended upon its size and pro- 
portions and also upon the manner in which 
the load was applied. The term elastic 
limit assumed a new significance when it 
became recognized that it could be defined 
and measured in different ways. In short, 
it was found that tests of materials must be 
made in a similar manner in order to ren- 
der the results comparable. This idea, 
although long recognized, has proved a diffi- 
cult one to realize. It has been discussed by 
many engineering societies, some of which 
have attempted to formulate standard 
methods. Finally the International Asso- 
ciation for Testing Materials was formed in 
order to study the whole subject and en- 
. deavor to arrive at conclusions that should 
be authoritative. 
In 1882, through the influence of John 
Bauschinger, a number of German experi- 
menters met at Munich and discussed the 
question as to how uniformity in the 
methods of testing materials could be pro- 
moted. Asa result of this meeting, formal 
conferences were held at Dresden in 1884, 
at Berlin in 1886, at Munich in 1888, and at 
Vienna in 1893, delegates from other Euro- 
pean countries being often present. The 
reports of the proceedings of these confer- 
ences, published in Bauschinger’s Mittheil- 
ungen, attracted wide attention, and the 
