Animadversions on Mr. Genetfs Memorial, fyc. 87 



is, in reality, no pressure of the atmosphere in Mr. Watt's 

 double acting engine, which Dr. Jones has here in view. But 

 if there is none, how can it abstract from its power ? And 

 again, if the piston works in the vacuum, as Dr. Jones has 

 told us it did, what difference can its levity, or its weight, 

 make in its power, if in vacuo, according to Newton, the 

 gravitation of a feather and of a ball of lead, compels them to 

 obey with the same speed, the proportional force that draws 

 them towards the center of the earth?" Here, by fair infer- 

 ence, the fallacy, that the pressure of the atmosphere ope- 

 rates, in Watt's single acting engine, is repeated. We are 

 also asked, how the air of the atmosphere can abstract from 

 its power ? — Will not the air pump, which is absolutely ne- 

 cessary to its action, and which consumes no inconsiderable 

 portion of the power of the engine, answer this question for 

 me ? Has not Mr. Genet himself answered it, in the following 

 quotation from the very page on which he makes the inquiry? 

 " The air that remains, or that is formed in the cylinder after 

 the condensation, or the air which enters the steam-vessels, 

 with the condensing water, and the gas, air, or steam, which 

 forces itself between the piston and the sides of the steam- 

 vessels, let the collar through which the piston-rod must 

 work, be made ever so tight and close, cannot be drawn out, 

 or excluded, entirely, and will always, in all kinds of engines, 

 oppose a gradual decrement to the descending power of the 

 piston." 



The philosophy of the concluding question, is much more 

 modern than that of Newton, or of any other philosopher 

 with whom we are acquainted, with the exception of Mr. G. 

 Newton never confounded momentum and velocity together,, 

 but taught that the former was compounded of velocity, and 

 quantity of matter. Where in his Principia, his Optics, or in 

 any other of his works, has he said, that a feather and a large 

 mass of metal, such as the piston of a steam engine, would 

 weigh alike, or descend with the same force, in vacuo? Real- 

 ly sir, it seems that there is more than one person in the 

 world, who might be benefitted by being " condemned to 

 to study again, his experimental and mechanical philosophy." 



" Dr. Jones garbles, when he says that I call a vacuum a 

 gas, and the vapor of water atmospheric, but he has not even 

 suspected that I consider atmospheric air as a compound 

 gas." I did not anticipate this charge of garbling, as I gave 

 the whole sentence in Mr. Genet's own words ; and if this be 



