THE 
AMERICAN 
JOURNAL OF SCIENCE AND ARTS. 
[THIRD SERIES] 
a 
ART. XXI.—On the Variability of the Ultimate Molecule; by 
Professor W. A. Norton. 
W.A 
I Proposs, in the present article, to adduce numerous facts 
which seem to afford decisive evidence that the ultimate mole- 
cules of bodies, under varying conditions of pressure and other 
relations to surrounding molecules, are subject to change in the 
inteusities of the forces of attraction or repulsion they are capa- 
e of exerting, at a given distance, on such contiguous mole- 
cules; while retaining the same temperature and the same 
chemical constitution. 
The first evidence I shall present that the ultimate molecule 
may, under certain conditions, experience a change in the in- 
tensities of its active forces, is derived from the facts and phe- 
nomena of the set, or permanent distortion of materials, which re- 
mains after they have been temporarily subjected to a force of 
tress, 
ditions in the application of repeated stresses, etc. The follow- 
lng are some of the principal facts and laws that have been ex- 
aT era determined. 
