August,
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ANALYTICAL EDITION
1944
A p p a r a t u s for Washing Selas Crucibles C. R. SCHLEY Lucky Heart Laboratories, Inc., Memphis, Tenn.
A
atrong acids or solvents which would damage the rubber connection should be added at such a speed t h a t the volume does not build up in the reservoir, and the liquid runs through the filter as soon as it is added. Unnecessary damage to the rubber connections between filter flask and trap is also avoided by the stem in the lower holder which conveys t h e wash liquid down into t h e flask and prevents splashing into the side arm.
RECENT article (1) outlines an arrangement for washing
Selas filtering crucibles by reverse flow. This laboratory has performed this task in a slightly different manner, which the author believes to be more convenient and perhaps more economical of material. The crucible to be cleaned is placed in a n inverted position with t h e top fitting into a circular groove cut into the top of a Walter-tvDe crucible holder held in a standard filter flask. The bottom df’the crucible is covered with another holder of the same type from which the regular stem has been removed. A shortstemmed funnel is placed upright in the opening of the holder. T h e roove in the lower holder is filled with a suitable liquid, the cruci%le is pressed down as suction is applied to the filter flask, and the desired washing medium is poured into the funnel.
LABORATORIES and NEW EQUIPMENT Hotel Association Testing Laboratory The Amerioan Hotel Association testing laboratory, which is part of the Department of Hotel Administration a t Michigan State College, East Lansing, Mich., is located on the college campus. Bernard R. Proulx is head of the department and Bruce Hartsuch is in charge of the laboratory and all tests. Established about a year ago, the laboratory is as yet meagerly equipped and uses considerable equipment from another department of the college, but when war conditions permit it is planned to equip it fully and make it one of the outstanding laboratories of the country. Tests of textiles and cleaning compounds, as well as other physical tests, are now being made.
Specimen Holder for Abraser A specimen table for the Taber abraser, that permits testing paper products for wear resistance in moist or wet condition, has been announced by Taber Instrument Corp., North Tonawanda, N. Y. Results of tests are reported either numerically as the number of wear cycles to produce a given amount of wear, or as loss in weight when weighed on a precision laboratory balance.
Autoclave A 1-gallon autoclave, made by the Industrial Machinery Co., 231oomfield, N. J., is now available for prompt shipment. It combines in its design, construction, and equipment the functions and usual features of large high-pressure aut,oclaves, sulfonators, nitrators, chlorinators, kettles, and similar equipment.
Tin-plated Panels Bright tin-plated sheet steel panels, approximately 31 gage and measuring 3 X 5 inches, are available in limited amounts from the Stewart Research Laboratory, P. 0. Box 173, Washington, D. C. They are used in flowout and flexibiiity tests of paints and varnishes, in kauri-reduction tests, and for filing samples for reference.
This arrangement utilizes equipment readily available and reauirine: no modification other than cutting the smrtll groove in one of the holders, which in no way interfereiwith its sui;sequent use 1
in the
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manner* LITERATURE CITED
(1) Benne, E. J., IND.ENQ. CHEM.,ANAL.ED.,16, 277 (1944).
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BOOK R E V‘I E W S Colorimetric Determination of Traces of Metals. E . B . Sandell. xvi f 487 pages. 15 X 23 cm. Interscience Publishers, Inc., 215 Fourth Ave.. New York, N. Y . , 1944. Price, $7.00.
This book is Volume I11 of “Chemical Analysis”, the new series of monographs on analytical chemistry and its applications being published by Interscience Publishers. I t is a worthy addition to their list, published or in preparation. The author’s aim is presentation of a “limited number of methods which . . . appear to be best suited for dealing with traces of metals. No one reagent is necessarily the best for the determination of an element in all kinds of samples or under all conditions, and consequently two or three methods are described. . for a number of the metals. The treatment is to a considerable extent based on the experience of the writer . . .” Part I is a general introduction. The four chapters deal with trace analysis (17 pp.), methods of separation (15 pp.), methods of measurement (40 pp.), and 19 general coloriinetric reagents (36 pp.). Anyone not widely experienced in colorimetric methods of measurement will find much valuable information in this section. The chapter on measurement seems the weakest, but obviously the present range and variety of instruments could not be covered in the space available. A comprehensive critical discussion of this subject is definitely needed. In connection with the stated limit of range of colorimetric methods, Mehlig showed the practicability of working with far higher concentrations of iron and of copper in ores. W r t 11, covering analytical procedures, includes methods for 45 separate metals and the rare earth elements. Since various metals (Ac, Cs, Hf, Ma, Pa, Ra, Rb, Sr, Th, Y) are omitted and only selected procedures are described. perhaps a more accurate title might have been “Selected Methods for the Colorimetric Determination of Certain Metals”. I t seems likely that many analysts will wish that here had been included methods for nonmetallic elements, such as the halogens, silicon, nitrogen, and phosphorus (those omitted are B, Br, C, C1, F, H, I, N, 0, P, Po. S, Se, Si, Te). A second volumd might be devoted t o these elements. In general, the information for each element is classified under separations, methods of determination, and industrial applications, such as rocks, ores, minerals, metals, soils, water, and biological materials. Adequate operating directions are given for applying the
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