84 Animadversions on Mr. Genet's Memorial, §c. 



cither his ignorance of the difference between the open ended 

 cylinder, practically called the atmospheric engine, and the 

 tight cylinder, called the double acting engine, or that he has 

 purposely selected the complicated operation of the double 

 acting engine, in which the pressure of the atmosphere is no 

 more used, or of the high pressure engine, (in which, on ac- 

 count of its overwhelming force, the pressure of the atmos- 

 phere is not taken into account, and the cylinder is left open 

 to the air,) for the unfair purpose of showing that my paral- 

 lel was incorrect, and my definition of the steam-engine inju- 

 dicious. Had he known, or candidly considered, that in the 

 open ended cylinder the direct force of the steam goes only 

 to raise the piston, and that the expansive force of that steam 

 being condensed, the vacuum created determines the fall of 

 the piston, under its own weight and the incumbent pressure 

 of the atmosphere, equal, on every square inch of the area of 

 the piston, to 1 5 pounds, he would not have asserted, ' that 

 the pressure of the atmosphere and the weight of the piston 

 were not necessary to Mr. Watts 1 engine, and served only to 

 abstract from its power. 1 



" There is in reality no pressure of the atmosphere in Mr. 

 Watts 1 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 New- 

 ton, the gravitation of a feather and of a ball of lead, com- 

 pels them to obey, with the same speed, the proportionate 

 force that draws them towards the center of the earth? 11 



Some of those who know me intimately, will smile at the 

 idea of my being charged with ignorance upon the subject of 

 the steam engine, by one who could write such paragraphs as 

 those just quoted. But it must be remembered that this is 

 from the pen of one who " is not a philosopher of common 

 stamp, 11 a member of several learned societies, and one who 

 has been the pupil, and the associate, of men who have great- 

 ly enlarged the boundaries of science ; who have illuminated 

 the world by their discoveries. Let all this have its proper 

 weight, as k appears to form one of the strongest points in 

 the argument of my antagonist. 



Mr. Genet says that " Dr. Jones has proved, either his ig- 



* Except on the area of the section of the piston-rod. — Ed. 



