46 The Amervean Naturalist. (January, | 
2P œ`, P and —P. The crystals are tabular parallel to the orthopin- 
acuid and are nearly always twinned, frequently yielding very compli- 
cated groupings. The color of the larger crystals varies from sulphur 
yellow to black. Their hardness is 6.5 and density 5.006. The pl 
of their optical axes is parallel to the clinopinacoid, and the double 
refraction is negative. The extinction is 8°-15° in obtuse £, and the 
pleochroism varies between dark-brown and oil-green. The minerals 
associated with brazilite are apatite, magnetite, perofskite, ilmenite, 
and a spinel. An analysis of the new minerals is promised shortly. 
Landauer’s Blowpipe Analysis.—This little book” will be 
cordially welcomed by English and American teachers in colleges 
which the use of a large manual of blowpipe analysis is undesirable. 
It is as suitable for classes in mineralogy as in chemistry, since it will 
enable the student to determine the composition of a mineral as rapidl 
as will the use of the great majority of Determinative Mineralogies 
upon the market. Moreover, it possesses one desirable advantage over 
compounds are made to serve as distinctive tests for them, in that it 
compels the experimenter to study the chemical nature of the sub- 
stance with which he is working. A mineral is a definite chemical 
substance. A student of mineralogy who is unfamiliar with the com- 
position of bodies with which he is working, though he may know 
considerable about their physical properties, is neglecting the founda- 
tion upon which his knowledge of minerals must rest. The little book 
before us is an excellent introduction to the larger works like those 
of Brush and Plattner. It is, besides, complete enough for most of 
the purposes to which such a book is usually put. Beginning with & 
good description of the apparatus and reagents necessary to blowpi 
manipulation, it follows with an account of the operations employe 
describes Bunsens flame reactions, mentions the distinctive tests for the 
various chemical elements, gives Landauer’s and Egleston’s schemes 
for the systematic examination of inorganic substances, and closes 
with tables exhibiting the reactions of the various metallic oxides, 
and in a condensed form the results of the different operations 
described in the text. The book must find a place in many labor- 
atories. 
“Blowpipe Analysis, by J. Landauer. Authorized English Edition by 
James Taylor. Second Edition. Macmillan & Co., 1892, pp. 14 and 173. 
