704 SCHOOL SCIENCE AND MATHEMATICS

An interesting feature of this publication is the set of units of libraryexperiences which accompanies this edition. These units provide practicaldrills and exercises in every known phase of educational research. Hereis a text which is admirably adapted to the library needs of every educatorand should be one of the must books in every schoolman’s library.

JOHN P. ALVIRPhillips High SchoolChicago, Illinois

SYMPOSIUM ON DIAMONDS, by Edward H. Kraus, Sydney H. Ball, LazareKaplan, Paul L. Hertz, Alexander Shayne, Chester B. Slaw-son, A. A.Klein, Harry Berman. A Reprint from The American Mineralogist, 27,162-191 (1942). Conducted as part of the program of the annual meet-ing of the Mineralogical Society of America, Boston, Mass., Dec. 30,1941.

As would be immediately inferred from the distinguished character ofthe roll of authors, this series of monographs is both interesting andauthoritative. After Prof. Kraus^ introduction, as Chairman, Sydney H.Ball discusses "Diamond Production" which he is probably in better posi-tion to know about than almost any other man. Lazare Kaplan, who cutthe famous Jonker diamond some years ago then tells of the "Cutting ofDiamonds." Paul L. Hertz of New York deals with "Diamonds in theWire-drawing Industry." This paper is illustrated w^th three excellent cuts."Diamond Dies in the National Defense Program" is Alexander Shayne’ssubject and Prof. Chester B. Slaw^on of the University of Michigan has"Diamond Set Tools" as his topic. A figure illustrates one such tool."Bonded Diamond Wheels" handles a comparatively new and rapidlygrowing mechanical use of diamonds as told by A. A. Klein of the NortonCo., Worcester, Mass., and Harry Berman of Harvard University con-cluded the symposium with an excellent discussion of "Evaluation Cri-teria" in which he is concerned with the factors that make industrialdiamonds more or less durable and valuable.Many of our readers should covet a copy of this most unusual reprint.

While no suggestion is given as to a possible source of such a supply itmight be that a fewr copies could be had on application to an author orto the publishers of the American Mineralogist, ’

FRANK B. WADE

GLIDERS FOR EVACUATION OF WOUNDEDGliders and small liaison planes, capable of landing on little emergency

fields or even on highways, lend themselves to probable use, in addition totransport planes, by the new Air Evacuation Group (Medical) w^ich willoperate under Brig. Gen. David N. W^. Grant, the Air Surgeon, to speedthe trip of wounded troops out of the fighting area, it is predicted inAmerican Aviation.An average transport, with two gliders, it is pointed out, could carry in

tons of vital supplies to fighting forces and take out scores of wounded oneach trip. Each evacuation will be under the direction of a flight surgeon,trained in the selection of cases and conversant with the effects of airtravel. Each of the larger planes will also carry an Army nurse and onetrained Medical Corps enlisted man.

Facilities to train the enlisted personnel for this special work will soonbe set up.