PRECISION SCIENTIFIC CO

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INSTRUMENTATION

OUTSTANDING ADVANCE MADE IN HOT PLATE DESIGN AND PERFORMANCE

the outside of the skin, local inhomogeneties are eliminated. The column is encased in a metal jacket fitted with a pressure gauge. Their Uvicord ultraviolet absorptiometer allows the identification of zones in the eluate from chromato­ graphic and electrophoretic column separations of substances absorbing ul­ traviolet light of 2537 A. Typical ex­ amples of such substances are cyclic hydrocarbons, nucleosides and nucleo­ tides, purines, pyrimidines, proteins and certain peptides, and some enzymes, conjugated fatty acids, hormones, ster­ oids, and vitamins. The absorptiometer includes a de­ tachable optical unit containing an in­ tensity-stabilized, low-pressure mercury lamp, liquid ultraviolet filter, a flow cell of quartz with a 0.09-ml. holdup, a vacuum phototube, and a power sup­ ply amplifier unit containing lamp volt­ age stabilizer and amplifier circuits. The output from the amplifier can be fed to a recorder for 10 mv., 100 m v , or 0-1 ma. or to a directly indicating meter. The L.K.B. paper electrophoresis equipment is widely used. In connec­ tion with the high-resolution buffer salts of the Aronson-Gronwall type serum proteins can be resolved into nine components. We saw several of these instruments in use in the famous Glostrup County Hospital near Copen­ hagen. Particularly fine conductivity cells with very small holdup are built by L.K.B. These are in the form of a fine capillary spiral for rapid tempera­ ture equilibration and are fitted with small platinum electrodes. Despite their fragility, they are mounted in molded plastic frames for convenient immersion in a thermostat and form a relatively rugged assembly. Many Americans are familiar with "Science Tools" published periodically by L.K.B. Some very scholarly articles on a variety of topics have appeared. At random we pick a few which have appeared in the past few years. "The Decay of Gadolinium-153," "Useful Simplification of the Method of Least Squares," and "Oxygen Tension (Blood­ less Determination of Arterial) by Polarography." To keep things interest­ ing, the April 1960 issue contained a problem—"On the Distribution of Gold Bars among Bank Robbers." The problem was posed in flawless English combined with authentic gangster ter­ minology. The correct solution re­ quired Diophantine equations and cor­ rect answers were received from Portu­ gal, Scotland, Holland, Germany, the U. S., Australia, and other places!

PRECISION SCIENTIFIC PRESENTS NEW T h e r m - # - P l a t e Hot P l a t e s

Therm - Ο - Plate Available in six sixes with heating surfaces from 5" χ 5" up la 12" χ Μ * . Choice of square or rectangular types in small or large s i » s .

NOW Precision Scientific offers new design features for greatly improved performance together with modern styling. Here are units built for continu­ ous duty and long service . . . available in a variety of sizes. NOW Precision gives you fully ad­ justable stepless heat control . . . temperatures maintained as selected . . . repeat settings with accuracy. NOW you benefit from even distri­ bution of heat with minimum possible temperature differential between center and edges.

Therm-O-Mix Combines an electric hot plate with a magnetic stirrer. Control to 700°F. Even stirring speeds to 1800 R.P.M. Has sepa­ rate controls. Two sizes with a 5" χ 5" or 7 V i " ν TViu

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NOW the heat is kept on the heating surface with sides, bottom and controls remaining cool . . . no direct metal-to-metal contact.

NOW four types and eleven sizes to meet every laboratory need . . . standard models . . . stirring-heating models . . . shaking-heating model. . . explosion-proof models.

Therm - Ο - Shake Has all features of a 12" χ 12" Therm-OPfate with a shaking hat plate surface. Temperatures to 800 F. Shaking speed of 200 oscillations per minute. Hot plate and shaking motor controls are separate.

THE ALL N E W

Therm-#-Plate Hot Plates

EXPLOSION PBOOF T h e r m

Write for Bulletin 609 for 12 pages of BUILT

3 7 3 7 W . Cortland Street Chicago 4 7 , Illinois Local offices in Chicago

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ANALYTICAL CHEMISTRY

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BY

PRECISION S C I E N T I F I C CO. · Houston

· New York · Philadelphia

Circle No. 67 on Readers' Service Card 132 A

Ο-Plate

Steam .heated hot plates for hazardous locations. No electricity required. No moving parts. Tempera­ tures to 2 5 7 F . Steam pressure range, 0 to 60 lbs. Sties 7" χ 22" and 12" χ 12".

PS

· San

Francisco