32 Mr, Herapath's Reply to X, [Jan.. 



reduce it to three inches. Then the volumes of the body in the 

 two states would be as the numbers 1000000 and 1. Therefore^ 

 taking this condensed volume into account, the law of tempera- 

 ture, instead of -V, or -5, ought to be -4999995, which differ- 

 ence in the law being neglected, would occasion an error of 

 ['6d&'p6inr^^ P^'^^ ^^ ^^^^ degree of Fahr. ; that is, on 480°, the 

 distance of my real zero from the melting of ice, the error would 

 amount to less than the -o-owo^^ of a degree. Therefore, grant- 

 ing to X. that gas does exist at the real zero, which, 1 think, he 

 will find I have never denied nor even questioned, my determina- 

 tion of this point cannot be in error the twenty thousandth of a 

 degree ; and I could easily show him, if necessary, that it can- 

 not err the twenty thousand millionth of a degree. In fact, if 

 the experiments of Messrs. Dalton and Gay-Lussac are correct, 

 the position of the real zero is correct. The position of this 

 zero may be proved without having recourse to any law or theory 

 of temperature whatever; but of this, I shall speak at another time. 



Now X. denies in toto the existence of this real zero, however 

 much experiments and theory agree, because we have never 

 arrived at it ; yet observe what he says in the eighth paragraph 

 of his first paper : " We find by experiment that the proportion '* 

 in forming water *^ of two of hydrogen to one of oxygen, holds 

 good whatever be the volumes we try, and thence ive clearly and 

 rightly infer that the same must be the case when the volumes 

 are irifinitely small or atoms." Who, I beg to ask X. has ever 

 experimented with single atoms? If no one has, how comes it 

 that X. can '* clearly and rightly infer " beyond the reach of 

 experiment, and yet another cannot? May we not from this, 

 "^clearli/ and rightly infer," that it is commonly much more easy 

 and natural to take things for granted, and without proof, which 

 favour one's prejudices, than to admit others, however well sup- 

 ported, that oppose them ? 



One or two curious conclusions I could draw from this para- 

 graph of X. were I inchned ; but it is nmch more consonant to 

 my feelings to stop short, than to use the privilege of my own 

 justification to draw unpleasant consequences from the opinions 

 of one who appears disposed to be liberal. I must, however, 

 beg to tell him, that I never ^' admitted that an atom may be 

 composed of particles." A particle is composed of atoms, and 

 may be of other particles ; but an atom, which is an elementary 

 indivisible body, cannot be composed of particles. I beg also to 

 observe, that 1 have never said, I beheve, ** that the particles of 

 a body in the solid move sv^^ifter than in the fluid state," though 

 such a thing is neither impossible nor absurd.'^ 



'' He finds," says X. p. 391, Annals for Nov. '' that within a 

 certain range gases go on expanding nearly as the squares of a 

 certain set of numbers. Now within the same range, the expan- 



* X.'s paper, Annalt ofPhilotophy for Sept. p. 22G. 



