438 
POPULAR SCIENCE REVIEW. 
honesty ; and when they turn from the letterpress to Mr. Ernest Edwards* 
excellent photographs, they can put the seal of association upon the facts 
they have gathered from Dr. Robertson’s ably- written memoirs. 
THE CONSTELLATION SEASONS.* 
M R. PROCTOR here gives us a series of thirteen carefully-drawn maps, re- 
presenting the relative position of the various constellations for nearly 
every night in the year. These maps do not, of course, contain all those 
astronomical details which are to he found in a perfect star-map. Such details 
would have been out of place ; the object of the author being to supply the 
amateur astronomer with a picture of the heavens at certain hours, so that 
he may study the more important star-groups. Each map contains the whole 
of the visible heavens at the hour and date mentioned beneath it, the centre 
being the point over the head of the observer, and the outline indicating the 
horizon. Each star is marked in its proper direction as regards the point of 
the compass, and is placed at its true geographical distance from the centre. 
Hence the student commencing observations at the hour and date of the 
map, soon makes himself familiar with all the constellations. The maps 
include stars of the fourth magnitude, and by an easy calculation they may be 
employed for other nights than those for which they are intended. In our 
early studies of the constellations we had only the assistance of Lardner 
maps, and we can therefore fully appreciate the value of Mr. Proctor’s 
excellent series. 
HOW TO MAKE A STEAM-ENGINE, f 
n ET7E remember that one of the earliest and one of the most cherished 
* ' ambitions of boyhood was the construction of a model steam-engine. 
This desire is by no means an uncommon one, and may, we believe, be 
classed with that all-pervading fancy of some boys, that to be a sailor is to 
enjoy the very acme of mortal happiness. The little book before us is 
intended to supply ambitious youth with the information necessary to 
understand a working locomotive, and to manufacture a model steam- 
engine. The elementary sketch of the history of the discovery of steam 
as a motive power is simple and tolerably free from error, but we fear that 
boys will find it difficult to understand a “ stoker’s” explanation of the 
principle on which u Barker’s mill ” revolves. To say that the rotation is 
dependent on u the well-known principle in mechanics that action and 
reaction are equal and in contrary direction,” is simply to put a stumbling- 
block in the young reader’s path. It is even worse, for it is no explanation 
* u The Constellation Seasons : an Easy Guide to the Knowledge of the 
Stars.” Edited by Richard A. Proctor, B.A., F.R.G.S. London : Longmans. 
1867. 
t u The Model Steam Engine : How to Buy, How to Use, and How to 
Make it.” By a Steady Stoker. London : Houlston & Wright. 1867. 
