REVIEWS—HANDBUCH DER MINERALCHEMIE. 541 
omissions) all the new analyses published since the issue of the last 
supplement of the Handworterbuch in 1853. The older analyses, 
moreover, have been re-calculated, and the formule are arranged 
throughout in accordance with modern views. The atomic constitu- 
tion of silica, Si O?, as now universally accepted in place of Si O%, is 
thus adopted; and that of zirconia is made Zr O?, in place of the 
older Zr 203. Zircon itself, in the classification, is removed from the 
Silicates, and placed with Rutile and Cassiterite amongst the Oxides. 
Some other changes of this kind might also have been appropriately 
carried out, not perhaps in the body of the work, but in the tabular 
outline of the classification. Mere chemical formule in themselves, 
It cannot be too strongly insisted upon, are no true exponents of 
natural affinities—witness, for example, the collocation of molybdenite 
with iron pyrites, and the wide separation of magnetic pyrites from 
the latter, as adopted by the author in his present work according to 
the orthodox but very artificial system so generally in vogue. There 
is some unknown quantity, as it were, within these formule-relations 
which at present eludes our grasp. The true part sustained by water 
in the constitution of hydrated minerals, for instance, remains still 
wrapped in impenetrable obscurity. Professor Rammelsberg discards 
the idea that this water is in any part basic; and he appears disin- 
clined to allow the union of hydrates with other compounds, as 
usually adinitted in the case of the serpentiues, &c. In malachite 
and blue carbonate of copper, nevertheless, not to mention other ex- 
amples, the admission of a union of this sort appears more natural 
than to suppose in these allied compounds the existence of two dis- 
similar carbonates. In malachite we have two atoms of copper oxide, 
one atom of carbonic acid, and one of water; in the blue carbonate, 
three atoms of copper oxide, two of carbonic acid, and one atom of 
water. If we do not admit the presence of the hydrate of copper 
oxide in these minerals, the above numbers yield, respectively : 2 CuO, 
CO2 + HO; and 3 CuO, 2 CO? + HO. But if we admit the 
presence of the hydrate, these formule: become CuO, CO? +CuO HO; 
and 2 (CuO, CO?) + CuO HO—each containing a carbonate of like 
composition. This is the usually received view. The true constitu- 
tion, however, may be in no way represented by these more or less 
imperfect guesses. 
The nature of this laborious treatise, as will readily be perceived, 
necessarily precludes any attempt at extract or extended analysis. 
