Cc ' PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
lite, he states that while in the proportions of silica and alumina 
they are the same, the aspasiolite contains a considerable quantity 
of water ; both mimerals also possessing, though in different propor- 
tions, magnesia and oxide of iron, the former some lime, the latter 
only traces of it; and he asks if the differences in other characters 
of these minerals may not be due to the water acting as an isomor- 
phous base as regards the magnesia, oxide of iron, &c. After inves- 
tigating the component parts of serpentine, he observes that if we in- 
fer that all the basic water of serpentine is replaced by magnesia, we 
should have the formula for olivine, so that we should expect these 
two mineral substances to have the same crystalline form, which, 
adds M. Scheerer, is the fact. This he considers as a proof of his 
new kind of isomorphism, so that olivine is to serpentine what di- 
chroite is to aspasiolite. 
Taking this view, M. Scheerer calculates the proportion of oxygen 
in more than one hundred minerals containing water, and examined 
with care, and infers that by considering this water as basic water, 
the formule become more simple, and more in accordance with the 
composition furnished by chemical analysis, than when we consider 
the water in a state of hydrate. From his researches he concludes 
that one atom of magnesia, or of protoxide of iron, manganese, co- 
balt, nickel, and oxide of zinc, may be replaced in this kind of iso- 
morphism, to which he assigns the name polymeric, by three atoms 
of water, and one atom of oxide of copper by two atoms of water*. 
Reasoning upon the water contained in many of the elements of 
granite, in which he includes mica, iron pyrites, talc, hornblende, 
schorl, gadolinite, orthite and allanite, M. Scheerer opposes the theory 
of granite having been in a state of igneous fusion, though he does 
not deny that heat may have given the humid mass of granite the 
plasticity and softness which it cannot be denied it must have pos- 
sessed, and thus he so far admits heat as having been an essential 
agent in the formation of granite. He considers that this pasty mass, 
impregnated with water and heated under great pressure, would melt 
at a temperature much less elevated than if, m other respects the 
same, it were anhydrous; remarking that from this fusion, which 
should not be confounded with simply igneous fusion, results would 
follow of a very different nature than if the mass cooled down from 
igneous fusion alone. The minerals which had the greatest tendency 
to crystallize, those of which the crystallme power was greater than 
the opposing action of the watery vapours, would be the first to sepa- 
rate. All the water, continues M. Scheerer, not appropriated by the 
minerals during their crystallization would be concentrated where the 
free silica abounded. ‘This silica would not become solidified until 
late, when the temperature of the granite was considerably reduced, 
and when the water not chemically combined with the component 
minerals had escaped from the mass, a process requiring a long lapse 
of time. M. Scheerer then applies this hypothesis to the alteration 
* In thus giving this view of M. Scheerer, it is but right to observe that it 
is opposed by Prof. Naumann and Dr. Rammelsberg, who consider that it requires 
further proof. 
