146 ON MR. EWART’S PAPER ON THE 
which it acts, in the direction of that pressure, 
several recent French writers, as Carnot, Navier, 
Coriolis, and others have made that principle the 
subject of their researches, showing its important 
applications to the science of Movers and Ma- 
chines. There is, however, no person to whom 
the public are indebted in so high a degree, for 
an exposition of this matter, as to M. Poncelet, 
who, in his “* Mécanique Industrielle,’”’ published 
in 1839, has shown the full application of the 
principle in its most important practical bearings. 
It has been lately most extensively quoted in the 
able works of Professor Moseley (Researches on 
the Theory of Machines, Phil. Trans. 1841, and 
Mechanical Principles of Engineering and Archi- 
tecture, 8vo. 1843), and in these the subject has 
been further extended. 
The union of a continued pressure with the 
space through which it acts has received various 
names on the continent as well as in this country, 
as “‘quantité d’action,” ‘‘ puissance mécanique,” 
“‘ quantité de travaille,” &c. The last of which, 
with its English translation, ‘‘ quantity of work,” 
or simply “ work,’’ has been used by Coriolis, by 
whom it was first so named, (Journal de l’ Ecole 
Polytechnique, 21° cahier,) and adopted by Pois- 
