powerful illuminated magnifiers - ACS Publications

POWERFUL. ILLUMINATED. MAGNIFIERS. FOR CRITICAL INSPECTIONS. 4V2 or 7x. Magnification. 115 Volt A.C.-D.C. Plug-in Model. Portable Battery Model...
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JUNE

1947

17 A

the analyst's column T T A D a nice visit a t the Bureau of Standards recently and ** talked with G. E. F . Lundell, F . D . Rossini, and Martin Shepherd. Many of us know of Dr. Rossini's work during the war with the preparation of pure hydrocarbon standards for the calibration of various physical instruments. This work had the active cooperation of the American Petroleum Institute and proved invaluable. I t is, of course, just as important in peacetime, and the work is being extended to compounds other than hydrocarbons. The care with which standards are prepared at the bureau must be a source of great satisfaction and pride to those connected with their preparation, in that every resource is employed to make sure that the highest purity is obtained. Organic chemists and analysts who work on organic problems and those connected with distillation, should read the following papers, published in the Journal of Research of the National Bureau of Standards by D r . Rossini and co-workers: Assembly, Testing, and Operation of Laboratory Distilling Columns of High Efficiency (Research Paper RP 1724, Volume 37, 1946). Determination of the Purity of Hydrocarbons by Measurement of Freezing Points (Research Paper RP 1676, Volume 35, 1945). Purification, Purity, and Freezing Points of 8 Nonanes, 11 Alkylcyclopentanes, 6 Alkylcyclohexanes, and 4 Butylbenzenes of the APIStandard and API-NBS Series (Research Paper RP 1760, Volume 38, 1947). I t is common practice to consider t h a t the center cut of a distillation is of the highest purity, but this is not always the case, as you will find after reading the last paper cited. The determination of purity by time-temperature freezing and melting curves is being used by more and more laboratories throughout the country because of the splendid work done by the bureau in demonstrating its value. The papers cited are, of course, b u t a small part of the work done by this important group at the bureau, but these in particular deal with techniques and methods which should be understood and used by chemists in every up-to-date research laboratory. AVE EXPECT to bring you soon an interesting paper by Dr. Shepherd dealing with the analysis of gases, comparing the accuracy and precision of the mass spectrograph with the more commonly used gas analysis methods. There should be more critical comparisons and evaluations of our various methods by qualified and unbiased analysts. Analytica Chimica Acta, an international journal devoted to all branches of analytical chemistry, has made its appearance. Printed monthly by the Elsevier Publishing Co., Inc., of Amsterdam and New York, the new journal will publish contributions in English, French, and German, with brief summaries in these languages. Paul E. Wenger, University of Geneva, Switzerland, is the editor, with seven assistant editors. The editors point out t h a t a large number of European publications dealing with analytical chemistry have ceased to exist, and it is their hope t h a t this new journal will help remedy this situation. The first issue has seven papers on general analytical subjects, including micro, with one general review paper on the present position of quantitative spectrographic analysis by J. Gillis, Université de Gand. This paper of 12 pages covers t h e present state of development of the instruments and methods used in spectrographic analysis. A selected bibliography of 76 titles covers t h e more recent publications in this country and abroad.

Associate Editor

POWERFUL ILLUMINATED MAGNIFIERS FOR CRITICAL INSPECTIONS

4V2 or 7x Magnification

115 Volt A.C.-D.C. Plug-in Model

Portable Battery Model

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USED BY..

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USED FOR..

CHEMISTS PHYSICISTS BIOLOGISTS INSPECTORS METALLURGISTS STAMP COLLECTORS

INSPECTIONS COMPARISONS MEASUREMENTS PHOTOGRAPHY ELECTRO-PLATING GRAPHIC ARTS

Shop and laboratory workers — in every field of the arts, industry, and sciences — are using these powerful illuminated magnifiers to improve observation. They instantly clarify and detect what the unaided eye is unable to discern. The 4Vfe power magnifier has a 2" field of vision with a working distance of 1 l/g". The 7 power magnifier has a 1 " field and a working distance of 3A".



Available w i t h Bausch & Lomb Achromatic Lenses Magnifiers powered with Bausch & Lomb Achromatic lenses are especially adapted for scientific use — for printers, engravers, lithographers, photographers, stamp collectors, etc. Lenses are finely corrected affording a flat, sharply defined field of view, eliminating all distortion and color. The mount is threaded for focusing. Cat. N o . 26300 2630! 26304 26306 26310 26312 26314 26316

Lenses Achromatic It

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Non-Achromatic

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Model Battery Battery Plug-in Plus-In Battery Battery Piug-in Plug-in

Power 4M 7 4M 7 4M 7 4M 7

Price $22.50 26.50 25.00 30.00 10.50 16.00 13.50 19.50

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ANDREW

TECHNICAL SERVICE 111 Ε. Delaware, Chicago 11