306 Mr. Herapath's Reply to Mr. Tredgold. [Oct. 



strated in my memoir to be owing to the numeratom of the 

 bodies ; that is, the number of particles which there is in a 

 ■unity of their volume." 



These extracts are taken out of near 40 letters which have 

 passed on this subject ; and except an acknowledged erroneous 

 mathematical charge made by a gentleman, whom for obvious 

 reasons, I do not mention, contain all the objections hitherto 

 raised. I hope, therefore, they will satisfy the world that diffi- 

 cult as the subject is, I have not, in the opinions of those who 

 are conceived to be our most scientific men, treated the matter 

 in a manner very easily to be refuted. In fact, the whole differ- 

 ence between me and certain members of the Council has not 

 been on account of any defined or undefined charge of error — 

 Under these circumstances, I trust that I may be allowed, 

 purely from a wish to avoid precipitate controversy, to recom- 

 mend not only Mr. Tredgold, and your correspondent X. to 

 re-examine their difficulties and objections, but likewise any 

 other individuals who may be disposed to honour my views with 

 their notice. 



At present I perceive both Mr. T. and X. have fallen into 

 errors and misconceptions ; and one, I regret to say, into misre- 

 presentations, which I would rather see corrected by himself 

 than by me. 



Though I have no intention now to enter into the subject, 1 

 cannot help noticing the new and peculiar manner in which Mr. 

 Tredgold has managed his " Refutation." Without advancing 

 one fact against my views, he propounds a new theory of colli- 

 sion, partly borrowed from mine, and partly the offspring of his 

 own imagination, but agreeing neither with the old theory, nor 

 with mine, nor with that of any other individual; and then he 

 tells us, not indeed in words, but in substance, that ' his conclu- 

 sions being most of them different from Mr. Herapath's, his 

 • (Mr. T.'s) Refutation is complete, and Mr. H.'s theory falls to the 

 ground.' 



" What kind of a theory," a friend asked me the other day, 

 " could you write to satisfy both Mr. T. and X. ? Would it not 

 be advisable," said he, " for these gentlemen to settle their 

 own discordances before they venture to attack another ? " — 

 (See their opinions of aeriform elasticity at the bottom of p. 131, 

 Phil. Mag. for Aug. and bottom of p. 224, Annals for Sept.) 



I now beg leave to inform your readers, that the paper attacked 

 has but one first principle, that of absolute hardness in the ulti- 

 mate atoms. The postulata, though they are put in this form, are 

 not, as I have in that paper hinted, incapable of being esta- 

 blished by rigorous demonstrations; but I chose this way 

 because, except the third, they are all Newton's maturest ideas;* 



* It has been usual to cite Newton as having demonstrated the repulsive force of 

 gaseous particles, but the following observations will show, that he did not at all consider 

 k as proved. " An riro Fluida Elastic* ex particulis se mutud fugantibus constent, 



