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Applied Physics Corporation/Pasadena/California

Radioactivity Measurements Made Faster, Cheaper with Vibrating Reed Electrometer

LETTERS

Measurement of radioactivity in radioisotope determination, reactor control, air contamination studies, oil well logrging·, and other problems in­volving· precise measurement of small currents, voltages and charges, such a s precise pH determination and mass s p e c t r o m e t r y , can now be· made faster, simpler and cheaper by using trie Cary Model 30 Vibrating Reed Electrometer.

Unusually high sensitivity plus high zero stability and ease of instal­lation and operation are responsible for the greater speed and saving's. The Model 30 detects as little a s 10"17

amperes, and measures up to 10-6

amperes with a precision of 1%. Zero drift is less than 0.2 mV in 24 hours and less than .02 mV per hour.

C 1 4 , H 3 D E T E R M I N A T I O N S SIMPLIFIED

One widespread application in which the Model 30 has been of par­ticular value is in determining· C14, H 3 , and S35. Wilzbach and his co­workers at Argonne ^National Labo­ratory have developed procedures* which simplify these determinations in a wide variety of organic com­pounds. Samples are converted di­rectly to a gas suitable for measure­ment with an ionization chamber and the Model 30. This simple procedure eliminates the necessity for use of a precipitate, with its inaccuracy and time-consuming, tedious preparation.

Since as little as 10"12 curies of radioactivity can be detected, use of expensive "tagged" materials can be greatly reduced, often enough to re­turn the cost of the instrument in a x*ei&Liv€iy snort time.

The Model 30 can be used in any l abo ra to ry and does not r equ i r e costly, vibration-free mountings o r other special conditions of installa­tion or operation. For additional in­formation on the Model 30, write for bulletinCEN-3 today. It gives you de­tails on applications, references, per­formance, operating principle, speci­fications, modifications, accessories.

•Wilzbach, Brown. Kaplan. Science. 118, 522-523 {19535 Wilzbach. Van Dyken. Kaplan. Anal. Chem.. 26.880 (1954) Wilzbach, Sykes. Science 120. 494-496 (1954).

The Cary Model 30 Vibrating Reed Electro-meter is capable of detecting a current as small as 1.0X10-17 amperes originating in a high impedance source. Charges as small as 5 X 10-'& coulombs and voltages as small as .02

AUTOMATIC SWITCHING EXTENDS RANGE OF

HIGH-SPEED RECORDER

Hi^h accuracy over a wide range of values is now possible with a high speed strip chart recorder which automatically switches between a series of full scale ranges of 0-110, 100-210 and so on up to 900-1010 millivolts.

Range switching of the Cary Model 39 multiple-rang-e recorder is accom­plished by limit switches at the ends of the recorder slide wire, so it automati­cally selects a higher or lower range when the recorder pen reaches either end of the scale.

One important application of the Model 39, for example, is its use with the Model 30 Electrometer to accurately measure very small currents by the rate of charge method over extended time intervals. Additional information on the Model 39 is provided in the bulletin de­scribed above.

g u c ^ ^ w ^ i ^ m e ^ ^ : l i f S t E C T R O J ^ JjlitTRA VIΟ ί CTlAlsÎÀJLyZ ERÏS

APPLIED PHYSICS CORPORATION / 3 6 2 WEST COLORADO STREET / PASADENA î / CALIFORNIA

Attention to the Humanities

DEAR S I R : The fact that C&EN covers the

whole field of the chemical profession makes i t an ideal place to promote the sentiment that, however important chemistry is, the chemist is of even greater importance for he is a man. The chemist is a member of society and should be interested in its well being.

Richard H . Robinson (C&EN, May 9, p a g e 1938) says "This lack of per­sonality in science has shifted the highlights in his picture from men, who can lead him, to things that can destroy" him."

Science in industry is proceeding with accelerated speed and is causing profound changes in our social life. Those taking a leading part in causing the alterations should take note of them and no t leave this matter to a few long-haired professors." Those whose ability has brought us such a wonder­ful standard of living could now turn their attention to the conduct of men.

An editorial in the Chicago Daily News for May 3 stated:

In New York, a teen-age gang member coolly shot and killed a decent and un­offending youth in the belief that he was a member of a rival gang. As he was be­ing taken away by the police, the killer was cheered by a group of admiring girls. . . . This episode may be considered to have nothing in common with the wave of lawlessness sweeping the South in con­nection with a telephone and a railroad strike. But diere is a connection. It is a sickness of society, rooted in the immoral and cynical belief that one's selfish objec­tives may be pursued by any means avail­able. . . . When the strike is over there may well be less resentment shown toward the goons [police were told that ex-con­victs were paid to wage war] than toward fellow workers who refused to walk out. . . . If the management of the struck firms were hiring ex-convicts to slug strikers and burn their homes, the country would ring with resolutions of denuncia­tion and demands for f^d^ral intervention. Where are these voices now?

Authorities are always reluctant to proceed against lawless strikers, be­cause this class has the most votes. Thus the "dictatorship of the pro­letariat," which the Russian politicians are bragging about is being promoted right here in our own country.

DONALD DAVIDSON Oak Path 111

Egg-Washing Beneficial

D E A R SIR: W e have read with some surprise the

item (News-Scripts, May 9 C&EN, page 2040 ) drawn from Chemical Age, which states that "Washing eggs on the farm injures their storing quality be-

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LETTERS ,

cause t he resistance of t he shell is im­paired."

Apparently the British writers have not kep t abreast of developments in this country. Extensive laboratory and field research, followed b y several years of successful use o f egg detergent-sani-tizers on the farm, has shown that eggs can b e safely washed on the farm. Careful studies demonstrate that prop­erly cleaned and sanitized eggs keep better in storage and maintain hig^Ler quality than do so-called "nest clean"

an abrasive metnocL

Importance of proper egg cleaning and sanitizing w a s recognized several years ago by Northeastern Poultry Producers Council. I n cooperation with several departments of agriculture they established a program for evaluat­ing cleaning materials a n d published a list of accepted cleaner-sanitizers. Many of the state agricultural experi­ment stations have conducted studies and writ ten favorable reports. Philadelphia, Pa. W. E. BOTWRICHT

Clorpactin Goes Worth

DEAR S I R : W e were much interested in your

excellent piece o n the American Polaf Basin Expedition ("The Coldest Anti­biotics—May 16, page 2 1 7 6 ) .

Regarding the statement, however, that "Pfizer has contr ibuted drugs and other medical supplies to keep the group on its feet and /o r paws," may we point out that it is not Pfizer alone that is keeping tr ie expedition fit.

W e would like to note the fact that members of the expedition selected Clorpactin as t h e exclusive antiseptic for use on the t r ip . F o r this purpose the Guardian Chemical Corp., Long Island City, Ν. Y., donated 200 bottles of Clorpactin, grade WCS-90 , to the expedition.

T h e selection of Clorpactin was based on t h e growing use of the new drug for t reat ing particularly stubborn in­fections in many fields of medicine, as well as for antisepsis in surgery. Neto York, N.Y. M I L T O N FEISTSTEB

Harvard Rounds Out the M a n

D E A R SIR: R e the identity of t h e chemist who

came to Cincinnati with a pair of pliers (see News-Scripts, April 11 C&EN) : He was John McCollum of Standard Oil Co . ( Ind . ) . This was John's first national ACS meeting, and I guess h e figured one ought to b e prepared for all eventualities. Xhis is what Harvard training does for one! East Lansing, Mich. HAROLD H A R T

2588 C H E M I C A L A N D E N G I N E E R I N G N E W S