1819.] History of Anthrazothionic Acid. 95 
but still in an arbitrary manner ; namely, that the hydrogen of 
the anthrazothionic acid, when it forms an anthrazothionhydrate 
of copper with the oxide of that metal in solution, deprives the 
oxide of only +ths of its oxygen, while the remaining 1th unites 
with the disoxygenizing medium, the presence of which is neces- 
sary. This we can do by making a stochiometrical calculation 
of the constituents of anthrazothionic acid founded on that 
assumption, and comparing it with the result which we obtained 
m sect. 24. When we calculated the constituents of anthrazo- 
thionhydrate of copper (sect. 16 and sect. 17), we found that 
1°51 of anthrazothionic acid, following the above-mentioned 
assumption, must contain in itself 0-067 of hydrogen. On that 
occasion I omitted the figure in the fourth decimal place alto- 
gether ; and to make the calculation more easy, I did not 
hesitate to admit an error of one or two unities in the third 
decimal place. But the accurate quantity of hydrogen which 
1-51 of the acid contains is 0:0678; for 10 oxygen requiring 
1-325 hydrogen, it follows that 0-512 oxygen (namely + of 0-64) 
must require 0°0678 of hydrogen; but if 1-51 of acid contain 
00678 hydrogen, 100 of acid must contain 4:49 of the same 
element. Now this differs only by one unity in the second 
decimal place from the number found in sect. 24 by a very differ- 
ent process. This exact coincidence leaves no doubt about the 
truth of our assumption. Were we to complete the reckoning by 
the application of the data obtained in sect. 24 for the other con- 
stituents, we should obtain the same, or very nearly the same 
numbers. Of consequence the existence of anthraxothion, at least 
in combination with the easily reducible metals by the exact 
agreement of the two modes of calculation, is placed beyond all 
doubt. 
Sect.27. The Constituents of Anthraxothionic Acid determined 
stochiometrically according to the Theory of Volumes.—In order 
to be able to transfer the constitution of our acid to the theory 
of volumes, which seems best adapted to exhibit a clear view of 
the composition of bodies as free as possible from all hypothetical 
a it will not be improper to lay the following observ- 
ations before the reader, in the first place, by way of introduction. 
The theory of volumes is founded on the assumption that 
bodies unite with each other in the state of gas, and in definite 
proportions. Suppose then that the weight of a determinate 
volume of atmospherical air at the temperature of 32° and under 
a pressure of 30 inches of mercury, be reckoned = 1-000, and 
that the absolute weights of all ee bodies in the state of gas, 
and under the same circumstances, be ascertained. These abso- 
Inte weights exhibit at the same time the specific gravity of each 
body, referred to that of atmospherical air as unity. The specific 
gravity of permanently elastic gases can be determined by the 
well-known method of weighing a determinate volume of each at 
@ given temperature, and under a given barometrical pressure. 
