394 Analysis of Scientific Books. 
Physical or External Characters occupy the next section. 
“ The properties of minerals are somewhat numerous.” Rather 
so,—witness the following table. Colour. Changeable Colours. 
Lustre. Transparency. Refraction. Form. Surface. Touch. 
Coldness. Odour. Taste. Adhesion to the Tongue. Soil. Streak 
and Powder. Distinct Concretions. Flexibility and Elasticity. 
Sound. Cohesion. Hardness. Frangibility. Structure. Frac- 
ture. Shape of Fragments. Tenacity. Magnetism. Electri- 
city. Phosphorescence. Specific Gravity. In all twenty- 
eight! We shall skim hastily over this long Wernerian cata- 
logue, referring our readers to the work itself, or any other 
which details and delights in all the minutie of the school of 
Freyberg, for more ample particulars, and leave their brains to 
comprehend, and their eyes to distinguish, if they can, the 
meaning and shades of ‘ bronze yellow, which is brass yellow, 
mingled with gray,” ‘* brass yellow,” being ‘ sulphur yellow,” 
(“‘ which is pale, and has a shade of green,”) “ with a shade of 
gray, and a metallic lustre.” 
Refraction. The remarks on this subject are, in general, well 
given ; though the conclusion of the following paragraph is a 
little whimsical. The author is describing the method of ob- 
serving the double refraction of crystals, when the two images 
are so close together as not to be perceptible by common means. 
Make a very small puncture in a card, or piece of pasteboard ; and hav- 
ing closely applied the card to that side of the crystal most distant 
from the eye, look through the crystal and the puncture at a candle, placed 
at some distance from the eye ina dark room. (A lighted candle,—else not 
visible—in a durk room!) The two images are quite distinct. p. 49. 
Hardness. Instead of the usual method by the file or knife, 
for ascertaining the comparative degrees of hardness of minerals, 
it is more definite to determine in what order they ‘‘ impress or 
scratch each other.” ‘ Thus, in the series, diamond, sapphire, 
chrysoberyl, garnet, quartz, feldspar, phosphate of lime, carbo- 
nate of lime, and sulphate of lime,each mineral is scratched 
by that which precedes it.” 
Magnetism. The author employs the term double magnetism, 
the result depending on the combined action of the magnetism 
of the earth, and that of a magnetic bar, to denote the method 
of rendering sensible extremely minute quantities of magnetism 
in minerals, suggested by Haiiy, and which we need not describe 
in this place; nor can we stop to particularize the merits of the 
next section, Electricity, of which it is sufficient eulogy to say, 
that Mr. Phillips has quoted no inconsiderable portion of it in the 
introduction to the second edition of his mineralogy. 
Section 3. Chemical Characters.—The first of these is fu- 
sibility, the chief instrument for effecting which, is the blow- 
pipe. Short directions are given for using that instrument and 
its accessory apparatus. 
