376 JAMES WATT. 
occasioned the Reasons of Moving Forces to be disin- 
terred from their dusty shelves. Without hesitation they 
pulled down their former idol; the Marquis of Worcester 
was sacrificed to the desire of annulling the claims of 
Solomon de Caus ; the bomb placed on a burning brazier 
with its ascending tube, ceased at last to be the true germ 
of the present steam-engine ! * 
As to myself, I do not grant that the man was of no 
utility who, reflecting on the enormous elasticity of steam 
when greatly heated, was the first to perceive that it 
might be used to raise great quantities of water to all 
imaginable heights. I cannot admit that no mention is 
due of the engineer who was also the first to describe a 
machine adapted to realizing such effects. Let us not 
forget that we cannot judge soundly of the merit of an 
invention, without transferring ourselves in imagination 
to the epoch in which it was made; without expelling 
from our mind for the time all the knowledge that subse- 
quent centuries have poured in upon us. Let us imagine 
an ancient mechanic, Archimedes, for example, consulted 
on the means of raising the water contained in a vast, 
closed, metallic recipient, to a great height. He would 
certainly speak of great levers, of single or multiplied 
pulleys, of a windlass, perhaps of his ingenious screw ; 
but what would be his surprise if to solve the problem 
some one would be content with a fagot and a match? 
* In Les Raisons des Forces Mouvanies, it is evident that De Caus 
ascribes the force which shivered the shell entirely to the air; and he 
seems to consider that the force of the air proceeded from the water 
which exhaled in it. M. Arago cannot be borne out in saying, of those 
who do not arrive at his conclusions, that ‘d’écarter tout nom Fran- 
¢ais”’ was their principal thought. We know not to whom he alludes 
in assigning such a base motive, but the assertion infringes greatly on 
the impartiality which he promised us.— Translator. 
