250 On the Cause of Chemical Proporiions. [Apiiir., 



learned by these experiments is, that it is not in our power to pro- 

 duce pure antimonic acid, nor an antinioniate which contains no 

 antimonite of the same base. 



Tiiese experiments then do not determine any thing respecting 

 the composition of antimonic acid, and though th.ey seem to agree 

 best with tiie notion that it con>ists of Sb -f 5 O, I thinli ana- 

 logy so strongly in our favour, that we cannot avoid adopting 

 Sb + (> O, as its true composition. Especially as at present wc 

 do not know of a single example of a radicle combined with 5 

 volumes of oxygen. 



If we calculate the volume cf antimony from the composition of 

 antimonious acid, it must weigh 1613. The oxides of this metal, 

 from what 1 have said, ought to be : 1. The suboxide, Sb + O? 

 2. Antimonious oxide, Sb + 3 O. 3. Antimonious acid, Sb + 4 0. 

 4. Antimonic acid, Sb + G O. In my former experiments, I 

 found that 100 parts of antimonious acid mixed with antimony in 

 powder and exposed to heat, oxidize about i jis much metal as the 

 acid contains, producing a fusible oxide, which [ considered as a 

 combination of antimonious oxide and acid, because its- properties 

 were different from those of pure oxide. But I have found that 

 the difference was occasioned by a small quantity of silica and 

 potash, wliich the fused Q^ide liad dissolved from the glass iij 

 wiiich the experim.ent was made. 



6. Tellurium. (Tc). — Tellurium has no other known oxide but 

 that which is formed by the action of nitric acid. This oxide has 

 the remaikal)le property of combining with acids as a base, and 

 ivith bases as an acid. In these last combinations, which I call 

 tellurates, the oxide of tellurium contains twice as much oxygen as 

 the base. Hence 1 conclude, that it contains two volumes of 

 oxygen. And as 100 parts of tellurium in my experiments pro- 

 duced 124'S of oxide, the volume of tliis metal ought to weigli 

 H0()-48. If on the other hand, we take as the base of our calcula- 

 tion the analyses of tellurate of lead, (in which i.'01'5 parts of 

 fused tellurate produced 157 of sulphate of lead,) it follows that 

 100 tellurium combine with 24*4 of oxygen, and that the volume 

 of the metal weighs 81 'J. But if the specific gravity be of any 

 value in such determinations, it follows that tellurium ought to 

 have the same weight as antitnony, because their specific gravities 

 ditier very little. Now if v.'e suppose oxide of tellurium to lie 

 Te -H 4 O, its volume would weigh from 1G13 to 1638. Future 

 experiments must decide this point. 



Tellurium is found in nature combi'ied with different metals, 

 and it has the property of uniting with hydrogen. Tellureted hy- 

 drogen, according to my experiments, is H + Te. The metallic 

 tellurets contain, according to the analysis of Klaproth, 2 Te, and 

 some of them 4 Te. 



7. Coliimlji'im. J (Ch). — We cannot calculate the volume of this 

 metal, because we do not know the pro])ortions in which it enters 

 into anv of its combinations , 



