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Tenth Edition, Revised
By FRANK A. WAUGH, M.Sc.
Including Many Chapters from Downing's “Rural Essays"
Those who have country places of their own, whether large or small, will appreciate the clearly written text-matter of this masterful work and the practical assistance it will give them in beautifying their grounds.
Downing & Waugh's “Landscape Gardening” has 439 pages, 6 by 9 inches, and is well illustrated, showing typical examples. Cloth-bound, $6.00 postpaid.
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Hom Intense Is Sunlight
Its intensity, of course, depends upon latitude, season, time of day, atmospheric conditions; but whatever it happens to be, it can be measured readily with
Leeds & Northrup Company's MACBETH ILLUMINOMETER
Illumination of any intensity, artificial or natural, is within the range of this useful instrument. Its scale reads foot-candles directly. It is provided with a reference standard lamp with which each observer standardizes the instrument according to his own visual perception. This is done wherever he happens to be-no photometric dark room is required.
The illustration shows one method for making a measurement. The illumination on the test-plate, mounted on a tripod, is being
measured. A translucent plate, mounted in
suited for investigations con-
Bulletin S680 describes the Macbeth Illuminometer in detail
Leeds & Northrup
Electrical Measuring Instruments 4901 Stenton Ave. Philadelphia, Pa.
With Lippich Polarizer, adjustable half shadow angle, Scale can be accurately read to 1/100th degree.
Repeated object lessons have demonstrated that nearly all progress in science has resulted in important advances in industry
GE Research Laboratory
Schenectady, N. Y.
Among the many products developed by the General
For further information address Supply Department, Schenectady Office.
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Instructive Books on Timely Subjects
Mysticism, Freudian- Sex and Sex Worship
ism and Scientific Psychology
By KNIGHT DUNLAP, Professor of Psychology at Johns Hopkins University, Baltimore. Author of “ Personal Beauty and Racial Betterment," etc. 150 pages, with special jacket. Price, $1.50.
By O. A. WALL, M.D., Ph.G., Ph.M., 625 pages,
This timely book analyzes the current Freudian movement in detail, and states in the light of analysis the fundamental principles of present day psychology. Written in popular style.
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