T EH
PERKIN-ELMER
INSTRUMENT DIGEST A c o n d e n s a t i o n of some of t h e a r t i c l e s a p p e a r i n g i n the SumTner issue of THE PERKIN-ELMER INSTRUMENT NEWS, a q u a r t e r l y p u b l i c a t i o n of The PerkinElmer C o r p o r a t i o n , m a n u f a c t u r e r s of s c i e n t i f i c i n s t r u m e n t s — I n f r a r e d Spect r o m e t e r s , Tiselius E l e c t r o p h o r e s i s A p p a r a t u s , U n i v e r s a l M o n o c h r o m a t o r ,
Norwalk, Conn.
Flame P h o t o m e t e r s , Continuous I n f r a r e d A n a l y z e r , Low-Level Amplifiers—as w e l l as A s t r o n o m i c a l E q u i p m e n t , R e p l i c a G r a t i n g s , T h e r m o c o u p l e s , Photog r a p h i c Lenses, Crystal O p t i c s , a n d S p e c i a l Instruments for t h e G o v j f n m e r t For f u r t h e r i n f o r m a t i o n , w r i t e The Perkin-Elmer Corp., N o r w a l k , C o n n .
July, 1951
Vol. 2, No. 9
New Meteor Camera Tracks ^Cosmic Dust"
Model 12 Spectrometer at Merck & Co.
INFRARED INCREASES PENICILLIN G PRODUCTION The accurate determination of the penicillin G (benzylpenicillin) content of a commercial fermentation broth has long been a difficult problem facing the penicillin manufacturer. Drs. N. R. Trenner and R. Chase of Merck & Co., Inc., Rahway, N. J. have a solution to this problem: the application of the isotope dilution principle which is practical, precise, reliable. This method of assay is cheap and practical to run when carried out on a typical control basis. As with all properly carried out isotope dilution methods, its accuracy (reliability) is equal to its precision which is, moreover, practically constant over the whole range of assay values. Because of its fundamental characteristics, the isotope dilution method has been used in connection with other difficult-toassay chemicals such as benzene hexachloride and nicotinic acid. Its future extension to other such problems seems highly probable. Merck estimates cost of a single analysis at $3.50 per assay, in only two hours time. As a result of the procedure, production has been raised at their penicillin producing plants. Y o u can receive the complete p u b l i c a t i o n From w h i c h these articles w e r e d i g e s t e d . Write The Perkin-Elmer Corporation, Dept. CEN, Main Avenue (Route 7), Norwalk, Conn., for your copies of INSTRUMENT NEWS. Featured in the Summer issue are: ULTRAVIOLET MICR0SPECTROSCOPY Analyzing cell components BAKER-SCHMIDT METEOR CAMERA Tracks 40 times more meteors INFRARED RAISES PENICILLIN PRODUCTION How Product Control Helps Merck SPECIAL OPTICAL DESIGNS Machine Tool Microscope
VOLUME
2 9,
NO.
29
Meteors as smtfti as buckshot will be accurately tracked by Harvard Observatory's new 5,000 lb. meteor camera, recently built by Perkin-Elmer. Extreme speed and wide field are characteristic of the Schmidt system used in the camera. The effective aperture of the lens is 12", its speed, f 0.67. It is so fast that the limiting exposure, even on a black, cloudless night, is 4 minutes. An ordinary telescope could be exposed for hours under similar conditions. The 52 degree field covered by the camera takes in about 1/10 the area of the visible sky, or 10,000 times the area of the moon. By comparison, the 200" telescope at Mt. Palomar can photograph only 1 20 of the moon. Dr. James G. Baker of Harvard Observatory, PerkinElmer's optical consultant, designed the Schmidt system used in the camera. Unlike any other camera, the optical system must be taken apart each time the camera is loaded, because the curved film holder and rotating shutter are actually in the midst of the optical system. After loading, the optics are automatically reset to within tens of thousandths of an inch of their former position. When in operation, the camera will be synchronized to move slowly across the sky in keeping with the movement of the
stars. These stars will appear stationary on the film and can be used as reference points for tracking fast-moving meteors. This is the third of Perkin-Elmer*s optical achievements within the past year to attract nation-wide attention. Last year saw the completion of the ADH 33" telescope. Earlier this year, the Transverse Panoramic Camera was turned over to the A ir Force.
Cell Conipounds Studied by M o n o c h r o m a t i c Light Precise localization and quantitative estimation of certain intracellular substances have been achieved through the use of microtechniques using monochromatic light by workers in the cytology laboratories of Columbia University. These substances can be traced in the life history of single cells and their changes in concentration correlated with such fundamental biological processes as growth, cell-division and secretion. The animal cells on which these studies were conducted range in volume from 200 to 30,000 cubic microns (2 x 10" 10 cm 3 to 3 x 10-« cm 3 ). Measurements on the cell components were made photometrically using a wavelength near the absorption maximum. Although any simple arc can be used as a light source, a more versatile apparatus is a monochromator with a constant emission source, using a photomultiplier detector. One result of these studies has been a correlation of desoxypentose in the nu(ADVERTISEMENT) » J U L Y 16, 1 9 5 1
Columbia's monochromatic
system
cleus with the chromosome number. Hence both large and small nuclei contain the same total amount of desoxypentose. Biochemical analyses of large samples of isolated nuclei support these conclusions. Digest of an article by Pollister and Ornstein, Columbia University, appearing in Summer 1951 issue of Instrument News. 2957
