804 
MR. BRODIE ON THE CONDITION OF CERTAIN ELEMENTS. 
that the peroxide of barium, the less reducible peroxide, is that v/hich under these 
circumstances is thus readily decomposed. 
Lastly, let me observe, that I have limited my assertions as to the nature of the 
elemental bodies, to the statement, that, under certain conditions, there exists a che- 
mical difference between the particles of which they consist. On the chemical nature 
of these particles I have offered no opinion. The apparent and obvious inference from 
the experiments is doubtless that the elements form a peculiar group of chemical sub- 
stances, consisting of similar particles or atoms in a state of combination, as other 
bodies consist of dissimilar. Of this view, in the early part of this paper, I have already 
spoken ; it is the hypothesis of Ampere. Many theoretical difficulties however meet 
us, when we come logically and consistently to carry out this idea to the explanation 
of chemical phenomena, especially to the phenomena of direct combination and to 
the simplest cases of chemical decomposition ; and it by no means follows that, 
although the apparent, it is the rational and philosophical interpretation of the expe- 
riments. Besides this view and that of Berzelius, there is yet a third hypothesis 
which we may form as to the constitution of these elements, namely, that they con- 
sist of yet other and further elements. On this view, the real fact which lay hid under 
these phenomena, might be the synthesis of the oxygen from the ultimate and further 
elements of which the oxygen consisted. In the present state of our knowledge it is 
useless to dilate on this idea; but on the assumption that the elemental bodies are in 
this sense compound, we may, I believe, account for all these experiments without ever 
assuming a chemical difference between two similar particles ; and it appears to me 
perfectly possible, that in such a constitution of the elemental bodies, these experi- 
ments, together with the phenomena of allotropy, may find their ultimate solution. 
