the EDITOR'S column
WELCH D. C. PANEL
METERS
• Accuracy 2 % of full scale deflection 1
SENSITIVE 20 MICROAMPERES MOVEMENT Γ Welch Model 350 Panel Meters are often used in teinporary "bread-board' ! assemblies and in "home-made* ' devices so common in electronics laboratories. In such work it is frequently more convenient to have an attached rather than a separate meter. Suitable for such applications as measuring grid currents and currents from photoelectric tubes and cells. They have alnico magnets, sapphire bearings, and especially selected pivots to mate possible the extremely sensitive 20 microampere moveiaent.
L.T.Hallett, Editor
MODELS 350—3!/2 inch round—2.4 inch scale. 351—3 inch square—2.4 inch scale 451—4Vi inch rectangular—3.5 inch scale MICROAMMETERS VOLTMETERS MII.LIAMMETERS -
Microammeters (>—20 up lo 0-500 Milliammeters 0-1 u p to 0-500 Ammeters 0-1 up to 0-30 Voltmeters, various ranges, 100 lo 50,000 ohms per volt Zero Center Ammeters DB Meters · Rectifier Instruments Special Scaled Meters · Thermocouple Meters À complete line of round, square, and rectangular meters is manufactured by Welch. WRITE FOR OUR METER CATALOG
W. M. WELCH SCIENTIFIC CO. DIVISION OF W . M. WELCH MANUFACTURING CO -^Established
NEW microfilm and aperture card combination makes possible man ual or machine sorting of spectrograms plus great savings in the bulk of paper records. This application was devel oped jointly by Marshal V. Otis of the Tennessee Eastman Co. Research Lab oratories, Kingsport, Tenn., and the Recordak Corp. The system was developed to meet needs for a new and improved standard system for recording, filing, and dis seminating reference spectral data. I t also meets needs for efficient searching and tabulating of selected spectrograms recorded in various formats by work ers in the field. I t provides a standard card for use in both large and small laboratories. Instrumentation advances have pro\rided chemical, physical, and analytical laboratories with a means of solving problems of great complexity. Further, expanded use of spectral data in ultra violet, visible, and fluorescence spectro photometry, coupled with the recent de velopment of low-cost, "bench top" in frared spectrophotometers, have con tributed to the growth of instrumental analysis. Large quantities of critical data from many organizations are be ing disseminated in many forms. To assure that these data are used effici ently, access to a centralized index must be provided and methods must be avail able to select only pertinent data. Prior to the development of this new system, one method used involved punched cards on which are coded con-
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Model No. 451
1880-
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HEVI-DUTY MOLYBDENUM TUBE FURNACE For long life, accurate control at temperatures to 3,000° F. Maximum Temperature Uniformity Low thermal conductivity of insula tion reduces heat losses and provides uniform temperatures in the heating chamber. Optional purge and waterjacketed chambers allow charge to be preheated and cooled in protec tive atmosphere. P r o t e c t i o n is Built In Special reactor transformer control system guards against overloading the molybdenum heating elements — supplies minimum initial voltage to cold elements — increases voltage as heat and resistance increase.
Easy to Operate, S i m p l e to Service Furnace may have either an auto matic i n d i c a t i n g a n d controlling pyrometer or manual controls and optical sighting window. Either sys tem will give accurate temperature control. Top of furnace is removable for easy access to elements.
Get full details on this high-temperature laboratory furnace in Bulletin 758. • Industrial Furnaces electric or fuel * Laboratory Furnaces • Dry Type Transformers * Constant Current Regulators
HEVI DUTY ELECTRIC CO. Milwaukee
i.Wisconsin
Circle No. 65 on Readers' Service Card VOL. 3 1 , NO. 4, APRIL 1959
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