348 On Chemical Comb mat ions. 



of sal amtnoniac, and all the others might consequfiitlv he re- 

 ferred to it by dilYerent decrements. The acid gases, tiie parti- 

 cles of whidi have a cube for thoir representative form, tend, on 

 the contrary, to combine with the anniioniacal gas in such a 

 way that the volume of one of the gases is double that of the 

 other, because the most simple polyhedron which we can form 

 with cubes is the hexa-tetrahedron which contains three of them. 



The composition of the gas formed i)y the meetin"; of oxygen 

 anfl chlorc, which Sir Humphry Ddvv has discovered and called 

 euchlorine, is one of the most remarkable, from the propor- 

 tions in volumes of its two component parts. According to his 

 aiialysis, five volumes of the gas which he submitted to the ex- 

 periment, gave, on being decomposed by heat, two volumes of 

 oxygen and four of chlore. Those relations seem contrary to 

 all analogy, and they seem to i)e inadequate to the explanation 

 of the composition of the particles of euchlorine, without ad- 

 v.iitiing tliat tiie gas analysed by this celfbratcd chcmi-^t was mixed 

 with a little chlore ; a supposition wiiich naturally occurs when 

 we recollect that the process Ijy Avh.ich this gas was obtained gave 

 a mixture of euchlorine and chlore, from vvhicii this last gas was 

 separated by shaking it over mercury ; a process which probably 

 did not trdce up all the clilore, and Vt-hich, besides, did not leave 

 Ruv method of ascertaining, even if successful, that the residue 

 of this operation was pure euchlorine. 



I think therefore that we must account for this analysis, by 

 supposing that the gas employed contained one-fifth of chlorc ; 

 and that, of the five vQinmcs. submitted to the experiment, there 

 were four only of a gas really composed of oxygen and chlore. 

 By supposing that the rej)resentative form of its particles is a 

 cube composed of two moieculcs of oxygen and five of chlorc, 

 we find that four j)articles of this gas ought to contain eight 

 molecules, i. e. two particles of oxygen and twenty-four mole- 

 cules, i. e. three particles of chlore : so that the decomposition 

 of four volumes of pure euchlorine would produce, upon tb.is 

 hypothesis, tv/o volumes of oxygen and three volumes of chlore. 

 The;;e three volumes of chlore united to a volume of the same 

 gas, which form.ed by its mixture with the four volumes of eu- 

 chlorine the five volumes which were operated upon, ought to 

 have given in the residue the four volumes of chlore found by 

 Sir Humphry Daw. 



The relation of three volumes of chlore and two volumes of 

 oxygen in the euchlorine, seems at first to present no analogy 

 with the relations which we observe in the combinations of the 

 other gases ; but this anomaly is only apparent, and merely 

 arises from the tetrahedrons of the chlorc, instead of i)eing se- 

 parated like the tetrahedrons from the oxygen, the hydrogen, 



and 



