EARLY USE OF STEAM. 369 



enters the gun barrel, and issues by the lateral horizontal 

 opening. Except as to intensity, this steam in escaping 

 will act like the gases disengaged from the powder in the 

 barrel of the gun when closed at the end, and pierced 

 laterally ; only, we should not have but a mere shock 

 as occurred in the instance of the sudden and harsh 

 explosion from the gun ; on the contrary, the rotatory 

 motion will be uniform and continuous, like the cause 

 which engenders it. 



Instead of only one gun, or rather instead of merely 

 one horizontal tube, let several be adapted to the ver- 

 tical rotatory tube, and we shall have, with the exception 

 of some slight differences, the ingenious apparatus of 

 Hero of Alexandria. 



Here we should, doubtless, have a machine in which 

 the steam of water creates motion, and may produce 

 mechanical effects of some importance ; it would be 

 truly a steam-engine. But let us hasten to add that it 

 would have no real point of contact, either in its shape, 

 or the moving power's mode of action, with the machines 

 of that kind now in use. If ever the reaction of a cur- 

 rent of steam becomes practically useful, we must, with- 

 out hesitation, refer the idea back to Hero ; though at 

 present the rotatory eolipyle can only be quoted here as 

 carving on wood is cited in the history of printing.* 



* These reflections are applicable also to the project that Branca, 

 an Italian architect, published at Rome, in 1629, in a work entitled 

 Le Macliine, and which consisted in generating a rotatory movement 

 by directing the steam issuing out of an eolipyle as breathings, or in 

 a current, or on the pallets of a wheel. If, contrary to all probability, 

 steam is some day usefully employed in the simple form of blowing, 

 Branca, or the author, now unknown, from whom he may have bor- 

 rowed the idea, will take the first rank in the history of this new 

 species of machines. Relative to the machines of the present day, the 

 claims of Branca would be quite null. 

 16* 



