CADMIUM STANDARD C For use with potentiometers, electrometers, a meters, or wherever else a precision standard of e needed. Negligible Temperature Coeff On November 13, 1916, three normal cadmiur were certified by the Bureau of Standards as differ of reference cells by less than one part in one hu three having the same value. On March 30 1920, after the lapse of three yea the same three cells were again compared by the B The maximum difference among the three was les hundred thousand, and the maximum difference value of 1916, was less than one part per hundred In other words, these cells showed a degree intents equal to that considered most highly satisfac able, in the very best type of precision resistan Bul. Bur. of Stand. Vol. 5, No. 3, p. 427.) The cells in question were in nowise special. of the materials regularly prepared by me, and w greater care than that constantly employed in the n dards. Marion Eppley (A.M., Ph.D.) Physico-Chemical Appa NEWPORT, R. I. Type T. R. Single Tube Rhe No Laboratory Equipment is complete without some variable resistances. To high standard of your outfit we suggest the addition of some "Becbro" Sliding Contact Rheosta (Tubular and Stone Types) Thousands of these rheostats have been manufactured and sold by us (the origi Manufacturers) to most all Universities, Colleges, Technical Schools and Industrial have always given entire satisfaction. Write for Bulletin C-5 BECK BROS. 3640-42 North Second Stree Philade H-ION DETERMINATIONS SIMPLIFIED The new Acree Apparatus with Pyrovolter Potentiometer is a unit outfit (not assembled), offering greater convenience and higher accuracy than any heretofore available. Even from a cost standpoint, it is worthy of your close investigation. Ask us for our New Price List of Apparatus for PH Pyrolectric Instrument Co. 636-640 East State Street Grahame Chemical Company 100 Rockingham Street Eastman Organic Chemicals OUR new price list now ready contains over 900 items. Among those not yet announced are the following: 938* Acetyl p-Aminobenzoic Acid 941* Acetyl n-Propylaniline 366* p-Chlorophenol P942 dl-Malic Acid 946* Methyl Cyclohexane 936* Beta-Naphthol Iso-Amyl Ether 947* Orcinol 944* Propyl Red (Indicator) 939 Urethane 940* Xanthone Of the above list all those distinguished by an asterisk have been prepared or purified in our laboratory. We have been handling Natural History Material of all kinds for the past fifty years, and so have accumulated a very complete stock. Our prices are as low as the quality of the specimens will permit. We are constantly preparing circulars and price lists covering our material in the different branches, which we will be pleased to send free of charge to the readers of Science. Some of our recent circulars: S-120 Special Minerals S-110 Complete Trilobites Dept, of Natural Science G. Lagai, Ph.D. 4C4-410 W. 27th St New York City 7-11 Spruce Street Sole Mill Representatives for Canada and I N NEW SERIES VOL. LIII, No. 1367 FRIDAY, MARCH 11, 192. SINGLE COPIES, 15 CTS. ANNUAL SUBSCRIPTION, $6.00 1776-1837). consistent of ery ave D er, Stanford University, Calif. FRENCH-ENGLIS MEDICAL DICTIONARY A dictionary of modern French medical and scientific terms has long been needed. Dr. Alfred Gordon, A.B., M.D. (Paris), has prepared one that will meet the requirements of all who have sought for such a work. The author is a physician thoroughly acquainted with the languages represented. It is not safe to depend upon the general dictionary for definitions of medical words. In the first place they contain so few such words that one seldom finds the term required, then, the real scientific significance is not pointed out. "Cloison," for example, is a dividing wall" or partition" in the general sense, but it is also the anatomical name for "septum"; "depot," ordinarily means "depository," but it has a chemical significance of precipitate" and a medical significance of "abscess." Words that are spelled alike in both languages should be studied because they tempt one to guess meanings that are quite wrong in most cases; rage" meaning meaning “rabies ; "chair" meaning "flesh"; "pain" meaning 'bread", are examples. The field of French medical literature is one that well repays study. Many who have been brought into contact with it during the war will continue to draw therefrom points of practical value. The French have a marvelous power of observation, and they record facts with great accuracy and precision. To derive full benefit, it is necessary to have for reference a book which gives the exact scientific definition. Dr. Gordon's dictionary gives the pronunciation of each word in English phonetics. It is ideal for the reference library, for the physician, scientist or student. Price, Cloth, $3.50 Postpaid. |