A CHEMISTRY SYLLABUS 189

J. H. Hildebrand: Principles of Chemistry (Macmillan).E. E. F. D’Albe: The Life of Sir William Crookes (Appleton).Sir William A. Tilden: Sir William Ramsay (Macmillan).S. A. Arrhenius: Chemistry in Modern Life (Van Nostrand).J. S. Chamberlain: Chemistry in Agriculture (Chemical Foundation).H. E. Howe: Chemistry in Industry, 2 vols. (Chemical Foundation).

COMMITTEE ON CHEMISTRY.JESSE E. WHITSIT, Chairman^ Dewitt Clinton High School, New

York.PROFESSOR QUAESITA C. DRAKE, Women’s College, University of

Delaware, Newark, Del.DR. BENJAMIN HARROW, Columbia University, College of Physicians

and Surgeons.CHARLES E. DULL, Southside High School, Newark, N. J.AUGUSTUS KLOCK, Ethical Culture School, New York.

Note. By vote of the Association, tlie Chemistry Committee is continued for another year.This action was talccn so that criticisms and results of experimentation may be collected andpresented at next year’s meeting. All teachers of chemistry are urged to cooperate, to tryout any of the ideas which appeal to them as worth while, to make suggestions that may leadto better outlines for secondary schools; and to criticize the Committee’s efforts with thissame end in view.

VIEWS RUBBER WITH X-RAYS.The question whether raw rubber, apparently the most formless of

substances, really has a crystalline structure appears to have been re-cently settled by actually seeing the crystal pattern produced on a lum-inous screen, according to Prof. George L. dark, of the MassachusettsInstitute of Technology. Dr. dark, in a report to the American ChemicalSociety, gives the credit for this achievement to Dr. Ernst Hauser, ofthe Metallbank of Frankfurt, Germany.

"Dr. Hauser and an .assistant imprisoned themselves in total dark-ness for five hours," said Dr. dark, "in order to make their eyes sensitiveenough to see the faint pattern of spots produced on a glowing screen ofcalcuim tungstate by X-rays which had passed through a sample of therubber."The effect, which is not the same as the familiar use of X-rays to reveal

the bones of the body, flaws in metal, etc., was described by Dr. darkas follows: "When a beam of X-rays pass through any material com-posed of crystals, such as salt or ice, a definite pattern is produced, andthe design of the pattern depends on the arrangement of the atoms in thecrystal. Noncrystalline substances, like glass, give no such patterns.Many materials and even rubber, have been studied in this way, andtheir patterns are more or less well known, but practically only fromphotographs. In the case of rubber it was especially important to seethe pattern directly with the eye, in order; to be sure that the crystalstructure was not changed, or even, possibly, produced in the rubber bythe action of the X-rays.

"Dr. Hauser and his helper not only subjected their own eyes to a longand tedious sensitizing process, but they used an X-ray tube’of extraor-dinary power, which consumed 130 milliampercs of current at a potentialof seventy thousand volts.""When they turned on the X-rays after their long imprisonment," said

Dr. dark, "the hitherto unseen pattern flashed out instantly, faint butclear, against the pale greenish glow of the screen."�Science Service,