On the Hj/jMhcsis of Gaseous Repulsion. 21 



the repulsive force of the particles of the cluster A on those of 

 the cluster B, will either continually diminish, become nothing, 

 and then become attractive, or it will increase to a maximum, 

 and then suddenly be converted into attraction. Either case 

 will render the intensity of the mutual action of the two clus- 

 ters not under the control of their distance, but of the distance 

 of the parts of the cluster A from one another ; a conclusion 

 openly at variance with facts. 



Some philosophers will perhaps observe, that they do not 

 imagine the attractive force of the particles of matter destroyed 

 pnd converted into a repulsive by the intervention of greater 

 space ; they allow that the attraction between the particles still 

 exists, but that it is overcome by the action of a discrete fluid 

 which they call caloric, and which they push into the pores of 

 bodies and put round the particles of matter in the form of 

 atmospheres. The particles of this fluid they suppose mutually 

 repel each other, while they attract and are attracted by the 

 particles of other matter. If any of this fluid come in contact 

 with a body, it will, we are told, in consequence of these two 

 properties, diffiise and extend itself throughout the whole of 

 the body; and, by the natural antipathy which its particles 

 have towards one another, will endeavour to make the parti- 

 cles to which it adhei'es recede and separate. Should there be 

 enough of this fluid to overpower the mutual attraction of the 

 parts of the body, these parts will separate mto the fomi of 

 gas, and stand at the gi'eatest distance fi'om each other which 

 the space will allow them. By these news it appears that the 

 attraction of the particles is not destroyed, nor even virtually 

 weakened, but merely exceeded by the repulsion in the calori- 

 fic atmospheres. Let, therefore, A represent the attraction of 

 a particle of matter, and R the repulsion of its calorific atmo- 

 sphere; and according as A is greater or less than R, we shall 

 have A — R for the tbrce with which it attracts or repels an- 

 other like particle. But in the gaseous state, the repulsion, 



according to Newton, is — ; in which x is tlie distance and B 



a coefficient uniformly the same for the same tenijx'rature. 

 Therefore R — A = Bj- . In this exjuession we are to ob- 

 serve that B is not a function of .r, but of some other inde- 

 pendent (juantitv; for instance, of the teiripcratiire of the air. 

 Consequently, if we imagine R to diminish until it be less than 

 A, this diminution cannot alter the form of the I'unctiou, and 

 it will therelbre thence be R — A = — B.i— ' . That is, the re- 

 pulsive force varying inversely as the distance will be changed 

 into an attractive l(>llowing the same law; supposing, as it 

 tomnionly does in algel)ruic functions, that Leibnitz's idea 



of 



