86 Animadversions on Mr. Genet's Memorial $c. 



own library, hear what he says, " The two different modes 

 of guiding, and using, the power of steam, improved in suc- 

 cession by Mr. Watt, and which have both, their respective 

 advantages, and disadvantages, and are both in use." &c. &c. 

 I do not suspect that this is " unfair''' 1 on the part of Mr. G. 

 or that he has intended to deceive, but I certainly do think 

 that he " has proved his ignorance of the difference between 

 the open ended cylinder, practically called the atmospheric 

 engine, and the tight cylinder, called the double acting en- 

 gine ;" and also that he is entirely ignorant of the structure 

 of Watt's single acting engine, which requires a tight cylin- 

 der ; that is, a cylinder closed at top, with the piston rod 

 passing through a stuffing box, just as in the double engine. 

 I presume that Mr. Genet once knew the action of the old 

 atmospheric engine; but if he did, he has now forgotten it. 

 His description of this, is equally incorrect with his account 

 of those of Mr. Watt. When attempting to point out my 

 ignorance, or want of candor, he says, "Had he known, or 

 candidly considered, that in the open ended cylinder, the di- 

 rect force of the steam goes only to raise the piston, and that 

 the expansive force of that steam being condensed, the vacu- 

 um 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 piston to fifteen pounds, he would 

 not have asserted, ' that the pressure of the atmosphere, and 

 the weight of the piston, were not necessary to Mr. Watt's 

 engine, and served only to abstract from its power.' " Cer- 

 tainly sir, all these things, I did not know, and I candidly, or 

 rather confidently, aver that they are not facts. Had this 

 description of the engine been intended as a travesty, its suc- 

 cess would have been perfect. I scarcely know how any one 

 could contrive to thread a greater number of errors, on a string 

 of the same length. The direct force of the steam does not 

 go to raise the piston ; the steam merely balances the pressure 

 of the atmosphere, and the piston is raised by a weight sus- 

 pended to the opposite end of the beam, which weight is con- 

 siderably heavier than the piston itself. The piston does not 

 '•'■fall under its own weight, and the incumbent weight of the 

 atmosphere," but, on the contrary, a considerable portion of 

 the pressure of the atmosphere, is expended in raising the 

 heavy counterpoise of the piston. The critique which follows, 

 serves to confirm, fully, this gentleman's want of information 

 upon the subject which he undertakes to discuss. " There 



