670 
it was unwise to increase unit names beyond 
the small number then well fixed in actual use. 
The subject has been much discussed and it 
is believed that the weight of authority is 
against it. The student of physics and me- 
chanics often loses sight of the thing and its 
derivation when a distinctive name is given to 
it, and while it is extremely convenient to dis- 
tinguish by names a few of the fundamental and 
most important units of measure the number 
should be kept at the lowest possible limit. 
Problems in Elementary Physics. By E. DANA 
Pierce. New York, Henry Holt & Co. 
12mo. 200 pp. 
This book is intended for use in secondary 
schools along with some suitable text-book and 
with laboratory exercises. It contains a toler- 
ably extensive series of problems illustrative of 
the quantitative character of the science and 
the exactness of its conclusions. They are, in 
the main, well selected and properly distrib- 
uted. Occasional definitions, formule or brief 
explanations are inserted, intended to be sug- 
gestive of the principles involved in the solu- 
tion of the problems. Some of the problems 
and statements are open to a criticism appli- 
eable to nearly all text-books of this class. 
They are mostly written by teachers in pre- 
paratory schools who have never themselves 
(it must be inferred) enjoyed a very thorough 
training in physics. This isshown in the com- 
mon failure to recognize the limitations to which 
almost all laws are necessarily subject, or the 
restrictions which must guard their enuncia- 
tion. It is impossible, of course, to assume 
that the teacher of elementary physics should 
know all of these, as it is impossible for the 
college professor, who is a specialist in the sub- 
ject, to know them, but it is not impossible to 
avoid some of the more common errors of 
statement, and it would be of enormous value if 
both teacher and pupil could know and never 
forget that most of the simple statements of 
physical laws, either by word or by formula, 
imply a simplicity of condition which never 
actually exists in nature. It requires some 
knowledge, but not much extra time and 
trouble to guard instruction in this line and the 
result is worth many times the cost. The lack 
SCIENCE. 
[N.S. Vou. VI. No. 148, 
of this is shown in a certain ‘cocksureness’ in 
elementary text-books and laboratory guides, 
as to what will or will not happen if you do so 
and so, and because the thoughtful and careful 
student is very likely to find thatif things do not 
happen as described he is in danger of losing 
both confidence and interest. Nearly all books 
of the class under consideration abound in ex- 
amples of this sort of thing. Instruction in 
physics in the secondary schools under the 
newer or laboratory methods is by no means 
the success that it is represented as being by 
those who have been its most active propagan- 
dists and the difficulty is not so much that lack 
of accurate scholarship has made a rigorous 
presentation of principles impossible, but rather 
that the great underlying philosophy of induc- 
tive science has continued unknown to both 
teacher and pupil. M. 
Insect Life. An introduction to nature-study 
and a guide for teachers, students and 
others interested in out-of-door life. By JoHn 
Henry Comstock, Professor of Entomology 
in Cornell University and Leland Stanford 
Junior University. With many original illus- 
trations, engraved by Anna Botsford Com- 
stock, member of the Society of American 
Wood Engravers. New York, D. Appleton 
& Co. 1897. 
In the college education of the present time 
nearly all science teachers are agreed that the 
introduction to natural history studies should 
begin in the lower schools, that instruction in 
biology should be as much a matter of require- 
ment in the preparation for college as the study 
of foreign language. Many instructors of science 
in the colleges, while thoroughly believing that 
the principle is an excellent one, are not at all 
enthusiastic in the enforcement of such require- 
ments, since natural history instruction in the 
preparatory schools is, as a rule, lamentably 
bad. A few perfunctory lessons in plant 
analysis, with neither enthusiasm nor knowl- 
edge on the part of the teacher, and much 
book work by rote is the rule rather than 
the exception, at least in the Western schools. 
It haraly matters what the boy or girl studies, 
so long as it is living organisms, if studied in 
the right way, and the right way is nature 
