396 Miscellanies. 
have often been disposed to question fhe propriety of denominating 
the study of minerals, a science ; and we are acquainted with Bota- 
nists who have actually abandoned it on the ground that its species 
were indefinite, and that no scientific characters existed for their 
recognition. 
We give the following as an outline of Mr. Shepard’s oun 
«He treats the science in five parts, under the following. seule 
isles viz. Terminology, Classification, Nomenelature; Character- 
istic and Physiography. 
Part I. or Terminology, embraces an explanation of the natural 
properties of minerals, or those which they exhibit while in their 
natural state. These are considered under three divisions; viz. 
1, such as refer to simple minerals; 2, such as refer to compound 
minerals; 3, such as are common to both. The first of these divis- 
ions, to which a section of seventy one pages is devoted, embraces 
the geometrical properties of minerals, or such as refer to space,— 
the relations of structure, of surface, and the phenomena of double 
refraction. In treating of the geometrical properties, or what is 
more usually understood as constituting the science of crystallo- 
graphy, the following order is pursued. To adapt the work to per- 
sons ignorant of solid geometry, a few pages are devoted to element- 
ary definitions in that branch. The following propositions are then 
laid down and lester viz. ‘1. Certain mineral species affect 
eculiar forms,” —2. sol different form - a found 
in different codioiducle — the same species,’ —3. he different crys- 
talline forms belonging to each species may be idee to be derived 
by certain laws from one type or fundamental form.” e number 
are produced when the replacements extend so far as to extingui 
the faces of the primary form. 
The imperfections of crystals in respect to their forms is next 
treated of, and the methods employed for ascertaining the angles of 
erystals. Then follows an account of the internal structure of erys- 
tals, or the laws of cleavage. Here the author has deviated from 
the practice of most writers on elementary mineralogy, in having 
ever in silence the subject of the origin of crystals through 
