Universal Projectoscope For Lantern Slides, Microscopic Work, Opaque and Vertical Projection THE THE ONLY LANTERN on the market that meets in a satisfactory manner the diversified requirements of educational work. It covers practically the entire field of projection. Every device calculated to facilitate rapid passage from one method of projection to the other has been adopted and from the standpoints of efficiency, economy, solidity of construction, rapidity and simplicity of operation it leaves nothing to be desired. To pass from opaque or vertical projection to regular or microscopic, and vice versa, it is merely necessary to drop or raise the mirror in the interior of the dark chamber. The change from lantern slide to microscopic projection is made by the simple act of swinging in or out of alignment the desired arm of the right angled objective or microscope holder. We have a pamphlet describing our full line of projection apparatus which we will be glad to send upon application. 39 W. Randolph Street :: :: CHICAGO, ILL. Please mention School Science and Mathematics when answering advertisements. EVER before has SO vast an NEV amount of knowledge made fascinating for children, been brought together as in the Every Child Should Know Books. It is the richest and most fascinating series for children that can be imagined. For the little student the series spreads a vivid, compelling, neverto-be-forgotten tale of the world-its mythology, its poems, its wars, its heroes, its facts, and its fancies. Features that recommend the series especially are the MODERATE PRICES at which they are sold, and the uniformly ATTRACTIVE BINDINGS and DECORATIONS. The subjects are as follows-the books sold separately or boxed in multiples of three: Check Those You Want Poems Every Child Should Know Songs Every Child Should Know Water Wonders Every Child Should Know Easy to Own You can get any one of the above books upon remittance of a Dollar bill, with the exception of the book on "Birds" ($1.20 postpaid) and "Water Wonders" ($1.10 postpaid). You can get three volumes (any titles) handsomely boxed, for Three Dollars ($3.00) or nine together, boxed, at the very special price of Eight Dollars ($8.00). The books may also be purchased on the instalment plan, $2.00 down, and $1.00 a month, until Nine Dollars have been paid for the set of Nine volumes. WRITE TO-DAY. Check the volumes you want on the above list, and fill in the following blank. Books will be shipped at once. CUT OFF HERE. DOUBLEDAY, PAGE & COMPANY, 133-137 East 16th Street, New York, N. Y. Please send via.... the books checked on the above list for which I enclose $. Name... Sch. Sci. & Math. 10-07 Address..... Please mention School Science and Mathematics when answering advertisements. PHYSICS IN THE SECONDARY SCHOOL-T. Quincy Browne TUNGSTEN SOME NOTES ON CHEMICAL LABORATORY EQUIPMENT Fletcher 717 724 729 730 733 744 745 748 750 751 ON THE DEVELOPMENT OF ELEMENTARY GEOMETRY 752 756 ..... AN APPARATUS FOR DERIVING LAWS OF PENDULUMS 760 THE TEACHING OF MATHEMATICS IN CALIFORNIA 762 GIFTS 769 GRAPHICAL ILLUSTRATIONS OF CONVERGENCE OF 770 A HIGH SCHOOL BOY'S PROOF OF THE PYTHAGOREAN 777 AN EXTENSION OF THE PYTHAGOREAN THEOREM-H. 778 PROBLEM DEPARTMENT—Ira M. DeLong 779 A METRIC CARAT-R. P. Williams .. 783 MAIL-STUDY AT THE UNIVERSITY OF WISCONSIN................ Read Our Advertising Pages We Have Several Special Bargains Advertised MEMBER OF THE EDUCATIONAL PRESS ASSOCIATION OF AMERICA PRICE. The subscription price is Two Dollars a year, if paid in advance, otherwise $2.50; single copies 25 cents. 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Material to appear in any number must be in the Editor's hands not later than the first of the second month immediately preceding. No numbers published for July, August and September. REQUEST. It is hoped that our friends and readers will try to increase the circulation of School Science and Mathematics among their friends and acquaintances. Sample copies will gladly be mailed to addresses furnished. Back numbers of School Science, School Mathematics, and School Science and Mathematics may be had for 25 cents a single copy. The Mathematical Supplements for 15 cents a copy. School Mathematics and Supplement, Vol. I, five numbers... $1.50 2.00 2.00 .75 2.00 2.00 1.00 Volume I,, No. 2, April, 1901, Volume I., No. 9, February, 1902, and Volume III., No. 1, April, 1903, of SCHOOL SCIENCE AND MATHEMATICS are out of print. For copies returned in good condition 50 cents will be paid in cash, or credit of $1.00 allowed on subscription. COLUMBIA OPTICAL DISK including 2 slotted plates, 4 lenses, 2 prisms and mirrors.... Above with refraction tank. .$14.95 17.50 Send for descriptive circulars. Let us quote on your Indianapolis Indiana 1330 THE NATURE STUDY LIBRARY Bound in Morocco This work was recently from the press of Doubleday, Page & Co. C. M. TURTON, 440 Kenwood Terrace, Chicago, Ill. Please mention School Science and Mathematics when answering advertisements. |