No. 424. ] NOTES AND. LITERATURE. 345 
For an elementary. treatise the book contains enough matter. 
The author unquestionably did well when he decided to limit. his 
descriptions to seventy-five species and make them fairly full rather 
than to attempt to discuss a greater number and devote only a few 
lines to each. _ There is nothing to criticise unfavorably in the chap- 
ters.on crystallography and on the physical and chemical properties 
of minerals. They are extremely brief, to be sure, but they are well 
arranged. ‘Their topics are well chosen, and the statements in them 
are accurate. The: tables are likewise good. . They contain no 
peculiar features that need elucidation. 
In the descriptive portion of the volume there is quite a little loose 
writing, which is especially to be condemned in a beginner's book. 
The order in which the minerals are taken up is that which seems to 
appeal to most writers of elementary treatises, It is not scientific, 
but it possesses the advantage of impressing on the student the 
economic importance of the different compounds. The important 
metals and their ores and compounds, other than the silicates, are 
treated together. Then come the silicates. The grouping of the . 
latter follows no general scheme. The order in which they are dis- 
cussed *is mainly intended to emphasize and fix in mind their rela- 
tionships and importance as rock-forming minerals." . There are 
some errors in this portion of the book and many irregularities in the 
headings of the paragraphs. Many chemical formulas are omitted 
where they might serve a useful purpose. This is particularly true 
in the case of the silicates, for which no composition formulas are 
given. In a few cases not even is the composition referred to. 
There is an unfortunate spacing of paragraphs, that undoubtedly 
will cause confusion. After the heading *'Feldspathoid Group" 
there is no spacing to indicate that this group does not include all 
the minerals following it to the end of the book. 
These faults, and others like them which might be mentioned, may 
seem very slight and trivial. As a matter of fact, however, they are 
serious in a text-book for beginners, since, though they may not teach 
error, they certainly lead to misconceptions on the part of the 
‘students. They may easily be corrected in a revision ; and a revised 
edition, in which these corrections are made, would prove a very 
satisfactory text-book. : 
The second part of the volume is devoted to the common rocks. 
It is so brief as to be of little value. The omission of a number of 
the rock names mentioned would not have injured the book in the 
least. Peperino, talus, detritus, eurite, ophiolite, itacolumite, and 
