��THE POPULAR SCIENCE MONTHLY.
��fire to the sawdust that was mixed with them.
The advantages of electric lighting for mills are dwelt on at some length, the dif- ferent systems being described and the cost compared. The latter contains the results actually obtained at the Globe Mills in Woonsocket, where the expense of lighting a weave-room three hundred feet by sixty- six, by gas, was nearly twice the cost of lighting the same room by electricity, gas costing $2.20 per thousand feet. Only one hundred and seventeen incandescent lamps were employed, where two hundred and six- teen gas-burners had been used, making the cost per light very nearly the same. The dangers of electric lighting are admitted, and the precautions to be taken are enumer- ated.
The second portion of the book treats of the restriction of injury from fire by means of the application of sound princi- ples of building pertaining to slow-burning construction. The features of bad con- struction and the elements of safe construc- tion are considered, and formulae are given for the strength of beams, planks, floors, etc.
The book is handsomely printed in large clear type, on good paper, and bound in " fiery red " cloth, which makes it rather suggestive. It is a book that could be read with advantage by many others than build- ers and owners of mills, and it is to be hoped that its practical suggestions may accomplish what its author aims at a re- duction in the number and extent of mill- fires, with the attendant loss of life and property.
Easy Star Lessons. By Richard A. Proc- tor. Illustrated with Forty-eight Star Maps and Thirty-five Woodcuts. New York: G. P. Putnam's Sons. 1882. Pp. 219. Price, $2.50.
The object of this last book of the dis- tinguished astronomer is to teach the star groups, and enable the learner to find them on the sky. Instead of the usual star maps that represent the entire visible heavens and require to be held upside down, or side- ways, in tracing out the constellations, four maps are given for each month of the year, namely, a northern, a southern, an eastern, and a western map, making forty-eight in
��all. The maps are printed in blue, the stars in white ; the principal stars of each con- stellation are joined by dotted lines, and the names of the constellation are given, but the usual imaginary pictures of bulls, fishes, and dragons are all omitted, so that the map more nearly resembles the sky than is usual. Lines are drawn to represent the horizons of New Orleans, Louisville, Philadelphia, and Boston ; also of London, England. The zenith of each place is likewise given. Sev- eral pages of letterpress accompany each set of star maps, and explain the method to be followed in tracing out each group, and woodcuts are employed in the text to exhibit the position of the larger stars as related to the bulls and bears of the sky. This method of separating the real from the imginary will be a boon to the star-gazer and the student, for it is very pleasant to know the stars to be able, like Milton's hermit, to
"... Bit and rightly spell Of every star that heaven doth show."
RErORT OF THE COMMISSIONER OF EDUCATION
for the Year 1880. Washington: Gov- ernment Printing-Office. Pp. 914.
The commissioner asserts that the im- portant relation which his department sus- tains to the interests of education is be- coming constantly more apparent ; and that the year covered by the present report was marked by a great increase in the amount and value of the information received at the office with reference to the conduct of education in our own and foreign countries, and by a corresponding increase in the pub- lic demand for the distribution of informa- tion. The department is endeavoring to secure a more exact particularity and defi- niteness in the educational statistics from the different States, so that they may show more clearly the condition of the schools, the proficiency of the pupils, and the degree of attention that is given to each branch of study. It has succeeded so far that the re- ports from Ohio give the number of pupils in each of the branches taught, and those of more than a dozen other States give ap- proaches to the result. Advance is claimed in the consideration shown in the arrange- ment of courses of study to psychological conditions and the necessities of pupil life. An approach has been made in the last ten