408 
POPULAR SCIENCE REVIEW. 
^^The Stars and Nebulae ‘^The Sun; ’’"“The Solar System;” Ap- 
parent Movements of the Heavenly Bodies ;” The Measurement of Time ; ” 
“Light — the Telescope and the Spectroscope;” “Determination of the 
Apparent Places of the Heavenly Bodies;” “Determination of the Real 
Distances and Dimensions of the Heavenly Bodies ; ” and lastly, “ Universal 
Gravitation.” The chapter on Light is a very model of how a book on optics 
should be written ; and by departing from the abominable system of repre- 
senting pencils of light adopted in most books, the author has rendered the 
action of lenses a simple matter for even the comprehension of a schoolboy. 
The frontispiece contains several well-coloured diagrams of solar, stellar, and 
nebular spectra, and will be useful to the teacher. 
Mr. Proctor distributes his half-hours over the following subjects : — A 
Half-hour on the Structure of the Telescope ; ” “ A Half-hour with Orion, 
Lepus, Taurus, &c. ; ” “ A Half-hour with Lyra, Hercules, Corvus, Crater, 
&c. ;” “A half-hour with Bootes, Scorpio, Ophiucus, Szc. ;” “A half-hour 
with Andromeda, Cygnus, &c. ;” “Half-hours with the Planets;” “Half- 
hours with the Sun and Moon.” Mr. Proctor is so well kno^vn as one of the 
best teachers, that it is almost unnecessary to say anything of the character 
of his “ Half-hours.” Like his other writings, they present a sort of royal 
road to the student. The author, when he takes up his pen, remembers 
the trouble and difficulties of his own first efibrts at observation, and he 
spares no pains to remove these obstacles from the young worker’s path. 
Indeed, of all our writers on astronomy, he is pa?' excellence the one of whom 
we should say, “ If you find any difficulty in carrying on your researches, 
consult him, and if it is possible, in the absence of verbal demonstration, to 
obviate your difficulties, he can effect it for you.” His chapter on the 
“ Structure of the Telescope ” should be read and remembered by everyone 
who wishes to understand this instrument. 
HOW TO AVOID EPIDEMICS.* 
"rrVGIENE as an art is a practical expression of the old maxim that pre- 
-LL vention is better than cure, and those who know anything of our 
great epidemics, or even of our small ones, are aware how very possible it is, 
by the adoption of certain simple rules, to stay the progress of even the 
most formidable infectious diseases. Some think that a work in which 
practical hygiene is dealt with, should be alone addressed to professional 
readers. But this idea is clearly a mistaken one. It is the public who first 
come in contact with the epidemic enemy, and it is unfortunately too often 
the case, that when the physician is called in, the infection has laid hold on 
the locality in which it first appeared. Now it is, to our mind, extremely 
advisable that the general public, and especially mothers of young children, 
should be not only able to recognise the earliest approach of infectious 
disease, and be acquainted with the most efficient measures for its ex- 
* “Notes on Epidemics for the use of the Public.” By Francis Ed. 
Anstie, M.D., F.R.C.P. London : Hodder and Stoughton. 1868. 
