130 BIOGRAPHICAL NOTICE OF 
powers it has attained in France, he was sufli- 
ciently conversant with the mathematics to read 
with facility most works, which were then the 
standard authorities in mechanics. Of the wide 
compass of his reading, and of the fullness and 
precision of his knowledge, his elaborate essay 
on the “Measure of Moving Force,” published in 
the second volume of our Memoirs, affords the 
strongest testimony. It is scarcely necessary to 
affirm of one, who had been trained in the school 
of Soho, that he was profoundly learned in all 
that has reference to steam, both as respects the 
higher philosophy of the constitution and laws of 
elastic fluids, and their practical application as 
sources of power. Mr. Ewart was the first to 
furnish an explanation of the singular phenomenon 
that the temperature of high pressure steam, es- 
caping from a small aperture falls considerably 
below 212°; from 290° Fahrenheit to 160.2 He 
suggested (Ann. of Phil., April, 1829) that the 
particles of elastic fluids have a tendency, when 
they are forced near to each other, to fly asunder, 
not only to their original distance, but beyond it. 
Thus high pressure steam, on suddenly removing 
all pressure, except that of the atmosphere, is 
converted into low pressure steam, and its tem- 
perature falls in conformity with the general law 
