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ARTICLE X. 
On the Allotropy of Elementary Bodies as one of the causes of 
the Isomerism of their Compounds*. By J. J. BERzEvtus. 
[Vetensk. Akad. Handling. f. 1842. Poggendorff’s Annalen, 1844.] 
IN the annual report on the progress of chemistry, presented 
to the Royal Academy of Stockholm in March 1840, I have pro- 
posed to designate by the term allotropic state, that dissimilar 
condition which is observed in certain elements, and long-known 
examples of which are found in the different forms of carbon, as 
graphite and diamond. I there endeavoured at the same time 
to show, that what we in compound bodies call isomeric modifi- 
cations, in certain cases depend upon the circumstance that the 
elements contained in one of these compounds exist in a different 
allotropic state from that in the other, whilst in other cases the 
isomerism distinctly depends on the atoms of the simple elements 
being combined in a different order, various examples of which 
I also brought forward, which it would be superfluous to enume- 
rate in the present instance. 
Although these dissimilar conditions, which I have here called 
allotropic, have long since attracted attention in one or two ele- 
ments, still they have been regarded as exceptions to the general 
rule. It is at present my object to show that they are not so 
rare, that it is probably rather a general property of the elements 
to appear in different allotropic conditions, and that, although we 
have hitherto been unable to obtain several of the elements when 
uncombined in their allotropic states, still their compounds indi- 
cate the same with tolerable distinctness. 
Since the discovery that the diamond, like graphite and char- 
coal, combines with oxygen to form carbonic acid, we are con- 
vinced that the ponderable material in them is one and the same 
element, notwithstanding the remarkable differences in their 
combustibility, their specific gravity, specific heat, and their be- 
haviour to light and electricity. So long as this was not known 
in the case of other bodies it was regarded as an exception. We 
* Trom the German by J. W. Griffith, M.D. 
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