DECEMBER II, 1913] 
NATURE 
421 
the lucid explanations. Sun, moon, and planets; 
tides, time, and eclipses; meteors and comets, 
and then the constellations, stars, and nebule, 
with their spectroscopic characteristics, are all 
dealt with in turn. Nor is the practically-minded 
neophyte neglected, for he will find some useful 
hints as to how to obtain and house his instru- 
ment, with some idea of the probable cost, based 
on actual accomplishments. The beginner should 
find little to confuse, and much that will enlighten 
him, although in the very brief survey of astro- 
spectroscopy he may wonder what such terms as 
“minimum-deviation ”’ (p. 303) mean, and it is to 
be hoped that he will proceed to make further in- | 
quiries into this most fascinating branch of the 
subject. The book is very well and profusely 
illustrated, some of the plates being in colour, and 
can be recommended as an excellent work for the 
serious beginner. In the copy under review the 
transposition of the top line on p. 24 to the top 
of p. 25 makes the text much simpler. 
(2) While Mr. Chambers aims at curing ignor- 
ance, Dr. Whiting seeks to prevent it, and to this 
end has compiled a set of educative, practical 
exercises in astronomy. The general aim of the 
author has been to formulate a set of exercises, 
e.g., the use of globes, plate-measuring, spectrum 
observing and plotting, the plotting of epheme- 
rides, sunspot numbers, &c., such as could be 
performed in day-classes independently of local 
weather conditions. In the hands of an enthu- 
siastic and imaginative teacher we can conceive 
that the book would be extremely useful, but we 
fear that in the hands of the ordinary student 
the exercises might easily tend to become more 
automatic than is desirable. Such an aim neces- 
sarily restricts the scope of the work it is possible 
to do, but in places, for example, in the exercise 
on spectroscopic work, we feel that the author 
has missed many opportunities where actual 
manipulation on the part of the student would add 
exceedingly to the interest and the educative in- 
fluence of the work. Our experience with students 
is that the reduction of a spectrum taken by them- 
selves is likely to awake far wider interests than 
is the copying, even in colour, of a chart from 
some text-book. The mere statement of “prin- 
ciples ” relating to such matters as velocity- and 
pressure-shifts, and the action of a magnetic field 
on radiations, savours of “cram,” and should, 
we think, find no place in such a book. 
(3) This is a charming book, telling the novice 
all that it is necessary for him to know, first about 
the planets in general and then in particular, and 
telling him in such language that he should never 
have to pause for a single definition or explanation 
that is not in the text. For each planet the 
NO. 2302, VOL. 92] 
family features are compared or contrasted, the 
physical condition explained, with the points 
where definite explanation is not yet forthcoming 
set out in clear and moderate language, and the 
ephemeris for a number of the coming years is 
very carefully interpreted; thus we find that on 
August 5, 1914, Mercury will be at western 
elongation, and “favourable for viewing,” while 
we shall have “splendidly brilliant oppositions ” 
of Mars in July, 1939, and early October, 1941, 
respectively. The author makes one feel at 
home with the planets by giving a very full intro- 
duction to every member of the solar family. and 
where figures are necessary, she robs them of all 
their awe by her familiar and easily-employed 
standards, leaving the reader of ordinary intel- 
ligence with a very fair idea of their significance. 
There is some repetition of facts in the book, but 
the forms in which they are stated are ever new 
and always interesting. Such a book, for its 
fund of information, its ease of. comprehension, 
and its delightful style, should be found in every 
school library and (astronomically) youthful circle. 
WituraM E. Rorston. 
OUR BOOKSHELF. 
Flies in Relation to Disease. Non-Bloodsucking 
Flies. By Dr. G. S. Graham-Smith. Pp. xiv+ 
292+xxiv plates. (Cambridge: University 
Press, 1913.) Price 1os. 6d. net. 
Tus is just the book for students who either are, 
or are to be, occupied with questions of public 
health; it is careful, well-digested, precise, and 
clear. Dr. Graham-Smith has practical know- 
ledge of the things that he writes about, having 
already published numerous experiments on the 
transmission of bacteria by flies. His book is 
freely illustrated by excellent plates and text- 
figures by Mr. Edwin Wilson. 
The evidence which convicts the common house- 
fly of causing heavy mortality in military camps 
seems to be complete; the same insect is also 
strongly suspected of being a chief agent in 
spreading typhoid, summer-diarrhcea, and other 
infectious diseases of cities. Visible proofs are 
here given that house-flies deposit vomit or faces 
wherever they settle, and this of itself shows how 
dangerous they may be when any disease pro- 
pagated by microbes is prevalent. It is to be 
hoped that the disgust which chapter vii., on the 
habits of flies, is sure to excite may rouse our 
sanitary authorities to root-out the breeding-places 
of the “busy, curious, thirsty fly,” which is at 
present treated with far too much: indulgence. Dr. 
Graham-Smith’s facts, handled by a newspaper 
writer not unversed in biological studies, might 
furnish telling articles, such as rendered good ser- 
vice in the campaign against malarial insect- 
infection, and in America (not as yet in England) 
against bacterial insect-infection as well. We 
