374 Mr. Moore on Instrumenls 



would fiirllier recommend, that this act of temper hig be per- 

 formed twice ; that is, at the usual time before grinding, and 

 ao-ain just before the hist pohsh is given to the blade. This 

 second tempering may perliaps appear superfluous, but upon 

 trial its utility will be readily admitted. We were led to adopt 

 the practice by analogy, when considering the process of mak- 

 ing and tempering watch-springs. 



LXXVII. On Mr. J. Murray's Commimicalions. Bi) 

 J. MooKE, Junior. 



To the Editors of the Philosophical Magazine and Jortrnal. 



Gentlemen, — iVIr. Murray does not seem to like notes of 

 interrogation; yet the very first sentence of his comnumication 

 to you in your last September Number, requires I should ask 

 him a question. I should not have noticed this sentence, but 

 I suppose Mr. Murray has a motive in using the word repeat. 

 He says : " I repeat that I see no necessity whatever for re- 

 publishing on the part of Mr. John Moore, Jun. that which X 

 had already done." I cannot find where he before has stated 

 that which he now says he repeats. This shows the propriety 

 of my asking Mr. Murray where is his previous statement? 



I have not copied the whole of Mr. Murray's paragraph, 

 because some of it is irrelevant to the subject. But when I 

 take the whole of it into consideration, I conclude Mr. Murray 

 means for your readers to suppose, that his apparatus and mine 

 are the same, and that we are only contending for the priority 

 of invention. A mere view of the two plans will convince any 

 unprejudiced person that they are unlike both in construction 

 and effect. 



My apparatus, by drawing and returning the pistons, ex- 

 hausts the lungs, and immediately I'efills them with fresh air; 

 and this change is continued as long as the pistons are thus 

 moved, without any further attention of the operator ; and 

 it also has the advantage of giving to the lungs a similar mo- 

 tion to that of br'^athing. 



Mr. Murray's apparatus is to give motion to the lungs, but 

 to exclude fresh air from them alter the fijst portion has been 

 injected ; without natural respiration returns. 



I will request you to refer to Mr. Murray's drawing and 

 description of his apparatus, Phil. Mag. vol. Iviii. p. 277, wliere 

 Mr. Murray's words are: "The stoji ci)ck is so constructed, 

 that when the handle is parallel with the pipe, as in the figure, 



there 



