64 M. Eerzelitis o/i Compounds 
erted by molecules of the second order, and that exerted by mo* 
lecules of the first, is immensely greater. Now, it is precisely 
the study of these decreasing afhnities which forms the object of 
mineralogical chemistry, and without which, that science can 
nefer arri\’e at any higher degree of perfection. The attempt 
to prove that the combinations which constitute minerals have 
been formed under the same laves which regulate the union of 
elementary substances in our laboratories, has met with a degree 
of success, sufhcient to remove all doubts concerning the accura- 
cy of its principle : but in order to reduce the results of not a 
few mineral analyses into conformity with these laws, the sup- 
porters of this opinion have been obliged to admit modes of com- 
bination, to which the chemistry of our laboratories offers no- 
thing analogous ; and it has been found, in general, that com- 
pounds in the mineral kingdom consist of a greater number of 
molecules than we have it in our power to combine by artificial 
means. The reason of our inability to form such combinations 
is not, that weak affinities are inert in our experiments ; but that 
they are destroyed by those greater forces of which w^e are ob- 
liged to make use, in order to obtain the combinations in an iso- 
lated state. Hitherto few trials have been made to produce ar- 
tificial compounds analogous to fossils ; but I am fully persuad- 
ed that such attempts wdll succeed, to a degree beyond what is 
hoped for in the present state of science. 
In my experiments upon the composition of silica, ( AfliandC 
k Fysili^ Kemi^^ tom. v. p. 500), I have proved, that if alu- 
mina, silica, and an excess of the carbonate of potash, be mixed 
together, and afterwards heated in a crucible of platina, till the 
mass has been, for some time, in a state of fusion ; w^e shall ob- 
tain a saline mass, of wdiich w'ater dissolves a portion, and leaves 
a portion undissolved, in the form of a white powder, w'hich 
may be called felspar with an excess of base. This pow'der is 
composed of silica, alinnina and potash, in such proportions, that 
the alumina contains three times the oxygen of the potash, and 
the silica contains a quantity of oxygen equal to that of the two 
bases together. This substance, then, in reality, being felspar 
deprived of tw^o-thirds of its silica, bears to it the same relation 
* Essays on Physics y Chemistry and Mineralogy^ a Swedish Journal conducted 
fey Messrs Berzelius and Hisinger. — Transl. 
