NEW BOOKS Determination of Tellurium.
W. L.
Anderson and H. E. Peterson. Bureau of Mines Report of Investigations 6201. Publications-Distribution Section, Bureau of Mines. J^SOO Forbes Ave., Pittsburgh 13, Pa. This report describes two modified procedures for determining tellurium in concentrations as low as half a part per million. In a volumetric method, the tellurium content of a solution is measured by the volume of a normal -iodine solution needed to oxidize the tellurium, changing the solution from brown to clear. In the other technique the tellurium in a solution is measured by spectrophotometry.
U. S. Government Publications The following can be obtained from the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C.
YOUR FORMULA FOR MIDGET PUMPS AND STIRRERS
. . . is very likely to come from Eastern. High efficiency in centrifugal and positive displacement pumps at mass production prices—versatility in variable speed stirrers—these are the elements which add up to the right combination of laboratory equipment. Compact design and remarkable performance make t h e m a d a p t a b l e where space and portability are factors.
Semi-enclosed, totally-enclosed, or explosion-proof motors powered from 1/30 to 1/3 h.p. offer a range of performance characteristics up to 20 G.P.M. at 15 P.S.I. Choice of metals, currents and voltages. Eastern Laboratory Stirrers are available for mixing small quantities of light liquids to ten gallons of viscous materials. Models available with non-sparking motors. Sizes are from 1 / 1 0 0 0 to 1/15 HP. Mountings may be either screw clamp or ringstand. Send for Free Folder
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International Scientific Organizations: A Guide to Their Library, Documentation, and Information Services. Prepared by the Library of Congress under a grant from the National Science Foundation. 794 pages. $3.25. This volume reports on the services of 449 scientific, technological, agricultural, and medical organizations. More than 3,100 bibliographical references are given, most of them with annotations. NBS Viscometer Calibrating Liquids and Capillary Tube Viscometers.
R. C. Hardy. cents.
22 pages.
1963. 20
This publication discusses the use of relative viscometers of the glass capillary tube type, pointing out various sources of error. Formulas are given for adjusting the viscometer constants for a number of different conditions of use. To determine absolute values with relative viscometers, the instruments must be calibrated with liquids of known standards. NBS supplies a series of 10 oils with viscosities ranging from 0.02 to 450 poises for this purpose. The Construction of Calorimeters for the Measurement of Absorbed Dose. Ben Petree and George Ward. National Bureau of Standards. 34 pages. November 1962. Technical Note 163. 25 cents. This note describes details of fabrication, auxiliary equipment, and per-
