370 JAMES WATT. 
HISTORY OF THE STEAM-ENGINE IN RECENT TIMES. 
In our manufacturing machines, in our packet-boats, 
in our railways, the motion results directly from the 
elasticity of steam. It is therefore of importance to seek 
where and how the idea of this power first arose. 
Neither the Greeks nor the Romans were ignorant 
that the steam of water can acquire a prodigious me- 
chanical power. They already explained, by the aid of 
the sudden evaporation of a certain quantity of this 
fluid, the frightful earthquakes which in a few seconds 
hurl the ocean beyond its natural limits; which over- 
turned from their very foundations the most solid monu- 
ments of human labour; which suddenly create danger- 
ous rocks in the midst of deep seas; and which heave 
up high mountains in the very centre of continents. 
Whatever may be said of it, this theory of earthquakes 
does not show that its authors had devoted themselves to 
appreciations, to experiments, to exact measurements. 
No one now ignores that at the moment when the incan- 
descent metal flows into the founder’s moulds of earth 
or plaster, a few drops of any fluid contained in them 
would suffice to occasion dangerous explosions. Not- 
withstanding the progress of science, modern founders 
do not always avoid such accidents ; how then could the 
ancients entirely keep clear of them? Whilst they cast 
thousands of statues, splendid ornaments of their temples, 
of their public places, of their gardens, of the private 
dwellings of Athens and of Rome, misfortunes must have 
occurred; the artisans discovered the immediate cause ; 
the philosophers, on the other hand, following out the 
spirit of generalization, which was the characteristic of 
their schools, saw in them miniatures, or true images, of 
Etna’s eruptions. 
