466 Mr. Herapath's Reply to Mr. Tredgold. [Dec. 



equal to A V the greater, the intensity of collision exceeds the 

 intensity when B»= o by A V. But Mr. T. acknowledges 

 when B v = o that the intensity is A V ; therefore when B» = 

 A V, the intensity isAV + A V = 2 A V, the same as in my 

 theory. Thus had Mr.T. argued correctly from his assumption, 

 he would, with the part he has, without acknowledgment, bor- 

 rowed from my theory, have brought out the same as I had, the 

 very conclusions he wants to refute. But to return : it is plain 

 from Mr. T.'s views here expounded, that the intensity of colli- 

 sion is greater the greater B v is ; yet from what he says of 

 the same thing in his first paper, I have shown that this intensity 

 is invariably the same for every value of B v less than A V. 

 Therefore it is evident that Mr. Tredgold's notions of collision 

 are such, that he cannot, under equal circumstances, at different 

 times, take like views of the same thing. 



Such is a fair representation of that part of Mr. Tredgold's 

 theory which is due to his own invention. Other absurdities 

 and strange paralogies I could easily adduce from Mr. T.'s 

 theory of collision were I disposed ; but I have passed them 

 over that it might not be said 1 strive to overcharge the picture. 

 What I have exhibited will be sufficient to show what confidence 

 can be placed in the observations and discoveries of Mr. T. ; and 

 as he seems not less determined to try to refute my theory than 

 ambitious to become the author of a new one ; these examples of 

 his success in that part of his theory which he has not taken 

 from mine, will, if they cannot convince him, demonstrate to the 

 world how well he can refute or discover. 



I shall not now, because it is extraneous to the subject, stop 

 to refute the absurd doctrine Mr. Tredgold would propagate in 

 the lastparagraph of his last letter, which, according to Mr. T.'s 

 discoveries, would render all philosophers, except himself, little 

 better than simpletons, and all works, except his own, visionary 

 and false. For the same reason I shall not reply to the illiberal, 

 unhandsome, and uncalled-for insinuation he has thought pro- 

 per, in a postscript, to add to his last letter. There is, however, 

 one thing too closely connected with the present subject to be 

 passed over; and as it is perfectly gratuitous on his part, will, 

 if not fulfilled, admit of but one construction. At the end of 

 his first paper he says : * / may also remark, that there is a 

 much more simple and consistent manner of accounting for the 

 greater part of 'the phenomena he {Mr. Herapath) has attempted 

 to explain." Of course Mr. T. must be acquainted with this 

 method, perfectly able to apply it, and thoroughly satisfied of 

 its truth ; otherwise he would not venture to speak so con- 

 fidently of it. Now I should be sorry to take Mr. T. at a dis- 

 advantage, and, therefore, if in next month's number he will 

 candidly acknowledge this to be a mistake, it may rest as it is. 

 If he do not, he will have the goodness to observe that the asser- 

 tion was totally unasked for, and irrelevant to the subject of his 



