NEWS
minor effects on spectra of variation in the position of substituents (1), while knowledge of the exact value of e is obviously essential to one who wishes to determine a compound quantita tively by spectrophotometry. It is unnecessary to give data in both tables and figures. Figures 1 and 2 show space-saving devices for use with simple and complex spectra. If there are so many spectra that their repro duction is wholly infeasible, provision should be made for their deposition with such an organization as the Amer ican Documentation Institute.
Analyzing for metallic elements day-in-day-out? HERE'S H O W T O C U T ANALYSIS TIME TO 2 M I N U T E S PER S A M P L E . . .
Summary
Current practices of presentation of electronic spectral data and the re trieval of such data by abstracting journals are discussed. On the basis of these findings, the following recom mendations are made. 1. The preferred unit of wave length is the millimicron. 2. Absorption at the maximum is best given in terms of molar absorp tivity or its logarithm. 3. The solvent or phase in which the spectrum is determined should be given. 4. Both the complete spectral curve and accurate printed data for wave length and absorptivity of the maxi mum are desirable. 5. Retrieval of literature data would be greatly facilitated by differentiat ing between types of spectra and by abstracting numerical data for absorp tion maxima. This manuscript was prepared by J. D. Cawley, Distillation Products In dustries, Rochester 3, Ν. Υ., to whom inquiries should be sent, and H. E. Ungnade, Los Alamos Scientific Labo ratory, Los Alamos, Ν . Μ.
Jarrell A s h
Atomcounter DIRECT READING
SPECTROMETER
With an Atomcounter, you can detect up to 30 metallic elements simultaneously and read individual concentrations from dials — all within two minutes. For metal producers, here's analytical speed made to order for controlling production alloys, checking material "spec'* conformance. For research or commercial labs, here's analytical speed to keep the endless volume of routine samples flowing smoothly. Wherever profits and efficiency are keyed to speed of analytical results, Atomcounter two-minute analysis gives you more time to accomplish more . . . handles more samples every hour . . . ends delay and drudgery. With an Atomcounter in your lab, high speed routine analysis becomes a simple, foolproof operation, easily mastered by any technician. And ' Atomcounter owners are assured of maximum dividends right from the start, for Jarrell-Ash engineers will tailor an instrument to your specific application, handle complete installation, and train your per sonnel thoroughly in Atomcounter operation and maintenance — all without extra charge. If you're concerned with routine analyses of metals, alloys, slags, ores, lubricating oils (for wear metals and additives), soils, biological plant ash, etc., invite a Jarrell-Ash analytical methods engineer to perform a comparative time-study right in your own lab. No obligation, of course, and chances are you'll be amazed at the findings. NOW AVAILABLE WITH OPTIONAL CAMERA FOR EVEN GREATER VERSATILITY:
Literature Cited
(1) Badger, G. M., Pearce, R. S., Pettit, R., / . Chem. Soc. 1952, 1112. (2) Blout, E. R., Eager, V. W., Silver man, D. C , J. Am. Chem. Soc. 68, 566 (1946). (3) Brode, W. R., J. Opt. Soc. Am. 39, 1022 (1949). (4) Doub, L., Vandenbelt. J. M., J. Am. Chem. Soc. 69, 2714 (1947): 71, 2414 (1949). (5) Friedel, R. Α., Orchin, M., "Ultra violet Spectra of Aromatic Com pounds," p. 6, Wiley, New York, 1951. (6) Hughes, Η. Κ., ANAL. CHEM. 24, 1349
(1952). (7) Klevens, H. B., Piatt, J. R., J. Chem. Phys. 17, 470 (1949). (8) Woodward, R. B., J. Am. Chem. Soc. 64, 72, 76 (1942).
Lets Atomcounter double as photographic spectrograph — ideal where flow of routine analyses is interrupted occasionally for an "odd sample" or research problem requiring photographic methods.
JARRELL-ASH COMPANY 32 Farwell S t r e e t , N e w t o n v i l l e 6 0 , M a s s a c h u s e t t s
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Circle No. 58 on Readers' Service Card VOL.
3 1 , NO. 2, FEBRUARY 1959
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