as connected with the Theory of Substitutions. 367 
their existence establishing the gradual passage from one to the 
other state. 
For similar reasons, in this memoir, the illustrations and argu- 
ments given have for the most part been restricted to one sub- 
stance, chlorine. It need scarcely be pointed out, in conclusion, 
that if the views here offered are true, very much of this reason- 
ing may be transferred to other bodies, as oxygen, nitrogen, hy- 
drogen, sulphur, &c. When oxygen and hydrogen are mixed, 
there is no disposition exhibited by them to unite, and this does 
not arise from their happening to have the gaseous form. As in 
the instance we have been considering, if they are exposed toa 
high temperature, or to the influence of platina, the active condi- 
tion is assumed with promptitude, and union takes place. 
The power which carbon possesses of throwing bodies into a 
completely passive state is far from being limited to chlorine. It 
re-appears in the case of sulphur. ‘The sulphuret of carbon yields 
to none of the tests to which we commonly resort for determining 
the presence of sulphur, for the simple reason that its sulphur is 
in an inactive state. This substance, moreover, serves to illus- 
trate what has been said of the gradual passage of bodies from a 
state of complete activity to one of complete inactivity. Berze- 
lins recognizes for it three different allotropic states; an alpha, 
beta, and gamma condition. In none of these is it in that condi- 
tion of absolute inactivity which it assumes in the sulphuret of 
carbon.* 
In offering these experiments and arguments to the considera- 
tion of chemists, I am fully aware of the magnitude of the change 
which would be impressed on the science generally, and espe- 
cially on several of our modern theories, by their reception. The 
long established idea of the immutability of the properties of ele- 
mentary bodies would, to a certain extent, be sacrificed ; and it 
is probable that before these results are conceded, more cogent 
evidence of the main principle will be required. In the mean 
time, however, it is plain that the admission of these doctrines 
throws much light on theories now extensively attracting the at- 
tention of men of science, and for that reason they commend 
* For these examples,—the chloride and sulphuret of carbon, I am indebted to 
M. Millon’s paper, “ Remarks on the elements which compose organic substances, 
and on their mode of combination.”” Comptes Rendus, T. XIX, p. 799. That 
chemist, however, gives a very different explanation of the phenomena involved. 
