156 
CHEMICAL PRINCIPLES. 
Combinations which the sulphur is proportioned to the total of the other 
ot tdhu'iuni. metals ; Tiir we know that sulphur, comoined with metal, like 
tellurium, requires twice as much oxigen to form sulphuric acid, 
as the metal to be basifiable oxide. Now, if we add the quantity 
of oxigen necessary to oxidate tellurium, and to form sulphuric 
acid with the sulphur, it requires 10'7d5 parts, and it we add 
together the quantities of oxigen necessary to oxidate the other 
metals, we shall havco 567 , or 5 3d7 X 1 1134, which coincides 
very well with the calculation, in the mineral named aiirum 
graphicum, we find 60 parts of tellurium combined with 30 
parts of gold, and 10 parts of silver. The oxigen necessary to 
combine with tellurium is 14'8, and that required to oxidate 
the gold and silver is 4 34. The analysis of Mr, Klaproth having 
been made on very small quantities, I have reason to think that 
there is some little error in the result of the an.dysis, and that 
these metals are so combined, that tellurium requires four 
times as mudi oxigen as the two other metals, that is to say, 
that these last are combined with twice as much tellurium as in 
the weisserz. 
There yet remains one more question to answer. Thesulphuret 
liketelluret of hydrogen, are bodies endowed with acid proper* 
ties ; but tbephosphoretand arseniuret of hydrogen, are, as far as 
we know, entirely exempt, notwithstanding that phosphorus 
and arsenic are more electio-negative than tellurium. This 
question is not very easy to resolve, and the only means proper 
to attempt to gain a solution, appears to me, by making use of 
the previous discovery of M. Gay l.ussac, that gaziform bodies 
combine either with equal volumes, or that one combines with 
2 or 3 times its volume, compared with the oiher.«. It appears to 
me, that this discovery may be employed as a theoretic basis for 
the laws concerning chemical proportions. From these theo* 
retie considerations, of which 1 hope to be able to make aa 
exposition in anotlier memoir, it appears that sul|)hur considered 
in the form of gas, combines with twice its volume of hydrogen j 
as it is with oxigen which absorbs twice its volume of hydrogen. 
Now, if we consider the oxide of tellurium composed of equal 
volumes of tellurium and oxigfen, it follows from what we have 
just 
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