IS 14.] On the Cause of Chemical Propor lions. 249 



exposed to a lieat sufficiently strong to reduce the whole yellovT 

 oxide to white oxide. It follows then, that antimonious acid is 

 composed of 



Antimony 80-129 100-0 



Oxygen ' 19-871 24-8 



100-000 



Now 18-6 : 24*8 :: 3 : 4; that is to say, that the oxide is com- 

 posed of Sb + ^ O, and the acid of Sb + 4 O. This agrees 

 vtTV well with the capacity for saturation of this acid. Since I 

 found that it contains 4 times as mucli oxygen as the base by wiiicli 

 it is neutralized. For 100 parts of antimonious acid arc neutra- 

 lized by 30 5 of potash. 



From analogy antimonic acid ought to be composed of Sb + 6 O. 

 But it is scarcely possible to determine this point by the quantity of 

 base with which the acid is neutralized. For it we suppose that the 

 acid, contrary to ?ll experience, is Sb + 5 O, the dilicrence of 

 oxygen in the base, in either case, would be only 452, or 4*73 at 

 most. Now it is very difficult to make analyses of the aniimoniates 

 which do not vary more than this. When 1 oxidated the metal, I 

 never was able to obtain more than 131 of yellow oxide from 100 

 of metal. In some cases 1 got no more than 128-5, or 129. All 

 these oxides may he nothing else than combinations of th.e antimo- 

 nious and antimonic acids, just as we have similar combinatiuris 

 between nitrous and nitric acids. I thought it likely that a more 

 rigid examination of the hydrous imtimoiiic acid would throw 

 some light on the subject. 



I prepared this hydrate in the following manner. I dissolved 

 antimony in nitromuiiatic acid, evaporated the solution nearly to 

 dryness, and then added water. When the mixture had become 

 clear, I decanted oft" the acid liquor. The white powder was then 

 dried. To deprive this powder of all nitric and muriatic acids, 

 from which it is not easily freed, 1 poured water U])on and dried it 

 a number of times in succession, till it had lost its acid and metallic 

 taste. 1 introduced this u-hite powder well dried into a glass retorr, 

 furnished witha tubidated receiver, into the tubular of ui)ich I h;id 

 put muriate of lime. I then heated the retort red hot. Tliere 

 condensed in the receiver and in the tube 5 per cent, of ])ure water. 

 The powder which was still yellowish, was strongly hi;ited in a 

 platinum crucible, anil left for residue yi-18 of antiinonious acid, 

 of a very white colour. 'J'he acid then had lost 3-82 per cent. t>f 

 oxygen. 1 repeated this experiment, but the results were always 

 diflereiit. The only constant circumstance was the ratio of the 

 water to the antimonious acid, which remained after the igiiilion of 

 the niai-s. This ratio was such, that the acid always contained four 

 times as much oxygen as the water. In the experin)ent which I 

 have relatoil, the oxygen of the water is 4-412, and that of the 

 antimoniou!. acid lH-1. Now 4412 x 4 = 17-648. All that I 



