Description of the First Steam-Engine. 43 



must, however, have been a great fire, as it would have been 

 attended with much danger to supply it with fresh fuel. It 

 is, therefore, reasonable to suppose, that from this great heat, 

 there would arise a continual increase of the expansive force of 

 the steam, and a continued decrease of the strength of the me- 

 tal of the cannon, until the strength of the cannon became un- 

 equal to the expansive strength of the steam, and, in conse- 

 quence thereof the cannon would give way and make " a 

 great crack." 



Prior to the date of the Marquis of Worcester's book, one 

 Branca, an Italian, applied the force of steam from a large 

 iEolopyle upon the vanes of a wheel, somewhat like those of 

 a horizontal wind-mill, so early as 1629. But in no way 

 could this manner of applying steam be transferred, or lead 

 to the construction of any one part of the Marquis of Wor- 

 cester's steam-engine, of Mr. Savery's, or of any other that is 

 entitled to the name of a steam-engine. 



The writer of this article, about thirty years ago, fitted up 

 a boat, or rather a canoe, to be wrought by spiral oars made 

 of sheet-copper ; but as the canoe was not of sufficient dimen- 

 sions to carry a person to work the oars, they were wrought 

 by means of a copper iEolopyle, placed on a fire-grate within 

 the canoe, that ejected steam against the vanes of a horizon- 

 tal wheel made of tinplate, and which communicated motion 

 to the spiral oars. 



At the time when the above experiments were made, the 

 writer of this had no knowledge of a similar experiment hav- 

 ing ever been made with the iEolopyle ; he first met with an 

 account of Branca's application of steam in the first edition of 

 Gregory's Mechanics, published in 1807. 



The ^Eolopyle experiment was an unprofitable waste of 

 steam, and could show but little of the effects of it ; whereas, 

 that of the bursting the cannon was a great first experiment. 



A. S. 0. 



September 30, 1824. 



