376 Miscellanies. 
« But while the alphabetical distribution has the advantage at least, 
of being independent of all scientific arrangement—concerning whose 
present existence many entertain doubts—the two tabular views, one 
at the commencement of this volume, and the other at the conclu- 
sion of the second, will present the species grouped in accordance 
with two classes of affinities, the first, the natural-historical, the se- 
cond, the chemical, resemblance. In the construction of these ta- 
bles, I cannot, of course, suppose that I have acquitted myself to 
the satisfaction of all, when I have but so imperfectly satisfied myself. 
‘“‘The chemical arrangement, however, is such as the present 
state of chemical science seemed to force upon me without much 
choice. A more extensive and accurate analysis of minerals, how- 
ever, will undoubtedly produce in it many changes, while also it 
— it will permit the composition of a considerable number of species, 
now left in uncertainty, to be expressed with atomic precision. * * 
“The natural-historical arrangment of the species is principally 
that brought forward by Mous. I have nevertheless ventured, 
though not without considerable hesitation, to propose a number of 
alterations, which will be obvious on a comparison of the two sys- 
tems. In making these changes, I have endeavored so to constitute 
the genera that the species of each should be bound together by a 
similar amount of resemblance. If in the execution of this difficult 
task, I have not violated the affinities of the species, an important 
advantage will have been secured, in the simplification of the no- 
menclature, by the great reduction of genera, especially in the or- 
ders, Ore, Pyrites, Glance, and Blende. 
“The formation of the new order, Picrosmine, appeared to be 
indispensable in providing a place for a number of species, which 
Mous had declined incorporating with his system from their defi- 
ciency in regular forms. ‘The production of Lusine-Ore was ren- 
dered necessary for a similar reason, in order to receive such species 
of the requisite structure and specific gravity, as are believed to owe 
their formation to the decomposition of other species. ‘The above 
mentioned writer does not allow such minerals, provided they are in 
a friable state, to constitute distinct species ; remarking of them, that 
‘it is in direct opposition to the principles of Natural History, to 
consider decomposed varieties of one species as varieties of another.” 
To the correctness of this as a general rule, I readily assent, allow- 
ing it full foree when the resulting mass is not homogeneous in its 
mechanical composition and at the same time destitute of a fixed 
chemical constitution.” 
