: the EDITORS column
Welch LARGE 12-INCH SCREEN
LECTURE-TABLE OSCILLOSCOPE
L.T. H a l l e t t , E d i t o r For all customary classroom demonstrations \N
INTERNATIONAL
INVESTIGATION
into errors in elementary organic microanalysis has been started by the International Union of Pure and Applied Chemistry's Division of Analytical Chemistry. The Division's Commission on Microchemical Techniques has set up a Study Group on Errors in Elementary Organic Microanalysis, which is intended to centralize, classify, and publish these findings for the benefit of all. The Study Group invites microanalysts of all countries to collaborate in this collective international task by sending in a, report of the results of their experiences. The report must be drafted in either German, English, French, or Russian. I t must be divided into as many separate parts as the errors under examination. Each p a r t must follow the headings of the following outline. 1. 2.
Element(s), amount(s) Microanalytical range (milligram, decimilligram, centimilligram) 3. Microanalytical balance employed (principle, model, installation, with or without air-conditioning, etc.) ; standard deviation of weights 4. Method employed—principle of mineralization (combustion), principle of t h e determination, apparatus, reagents, method of operation, etc. 5. Type of error studied—systematic or uncertain errors a:ïecting t h e accuracy or precision of the results 6. Order of algebraic magnitude of t h e systematic error, standard deviation or possible limits of t h e uncertain errors (errors of chance) 7. Sources of error, real or apparent. All of t h e factors of error must be retained, especially those which a p pear in the following unlimited list: Order of magnitude of t h e contents to be determined Physical properties of t h e compounds analyzed (condition, vapor pressure, h y groscopicity, triboelectricity (static electricity) etc.) Structures of the compounds analyzed Presence of interfering elements Presence of interfering functional groups Principle of the method of mineralization (combustion) employed Principle of determining the end product Reagents employed (nature, degree of purity, source) Other chemical products employed
Compare it with the standard 5-inch scope you've seen using up to now! write f o r descriptive circular 12-inch screen faces class. 3-inch monitor screen and all controls on rear panel for instructor's convenience. Controls operate 12-inch and 3inch tube simultaneously. No. 2 1 4 0 A
Controls and operating characteristics comparable to t h a t of average 5-inch oscilloscope. All components chosen with generous ratings to insure reliability. Net weight: 80 pounds.
Lecture-Table Oscilloscope
Each, $ 3 9 0 . 0 0
THE WELCH SCIENTIFIC COMPANY ESTABLISHED 1880 MAIN OFFICE: 1515 SEDGWICK STREET, DEPT. A-1, CHICAGO, ILLINOIS, U.S.A. 60610 NEW YORK OFFICE: 331 Ε. 38ΤΗ ST., NEW YORK, Ν. Υ. 10016 Manufacturers of Scientific Instruments Laboratory Apparatus
LOOMIS IDEAL PRESS for
FORMING KBr PELLETS • Pellets for X-Ray* and Other Analysis S h o w n — 2 0 Ton Lab Press with New
• Plastic, Ceramic and Metal Forming • General Lab Use
Compact
Power
handwheel and
50
Unit a n d accurate
adjustment. ton
models.
Also
30
Heating
platens o p t i o n a l .
I Accessories for temperature, pressure, extrusion testing units, etc. are available for all models.
WRITE
LOOMIS 22 RT. 4 6
* For better resulb use Loomis Λ VA" precision x-ray pellet die
F O R BULLETIN — DEPT. A
ENGINEERING CApitol 6-8660
& M F G .CO. CALDWELl, NEW JERSEY
Circle No. 58 on Readers' Service Card
VOL. 36, NO. 4, APRIL 1964 ·
89 A
