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. 



