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ANALYTICAL CHEMISTRY
so that the sirup is just 0.25 inch from the top, This will prevent a n y lens effect of the meniscus from interfering with t h e reading. After the level has been adjusted, t h e tube should be checked visually t o make sure that t h e surface is flat. This can be done by looking down through the full length of the sample at the bottom of the tube, which should appear as a smaller circle inside the mouth of the tube. If the bottom cannot be seen through
the mouth of the tube or is distorted, the surface is not flat and must be scraped. The glass sheet protecting the photocell must be cleaned carefully and the bottoms of the sample tubes must be kept clean to prevent partial blocking of the photocell. This method has been used daily for the past two years with emellent results on sirups in the RaumE range 20 t o 41.
A Text-book of Practical Organic Chemistry Including Qualitative Organic Analysis. Arthur 1. Vogel. xxiii f 1012 pages. Longmans, Green and Co., 55 Fifth .4ve., New York 3, N. Y., 1048. Price $10.50.
methods of manulactuie, which could not be adequately treated in one volume and still do justice to the other material covered. Considerable, although by no means complete information is given on such compounds as cyanamide, dicyandiamide, guanidines, andmelamine, which even 10 years ago were practically rare chemicals but are now produced in considerable quantity. As in the first edition the chemistry of the cyanides, cyanates, thiocyanates, and their complexes has been treated extensively and brought up t o date. This portion of the book is outstanding and references to the scientific literature are extensive and complete. The analytical section has been expanded to include the newer organic compounds. The author points out in the introduction that “several of the methods when used for the first time require manipulatory practice, however skilled the hands.” This is especially true of the newer organic compounds. No one active in the field of cyanogen compounds can afford to be L. J. CHRISTMAXS without the book.
A few remarks taken from the Preface will reveal the purpose and general contents. “Many of the new procedures and much of the specialized technique developed and employed in (the author’s) researches are incorporated. . .It is not expected that the student will employ even the major proportion of the operations described, but a knowledge of their existence is thought desirable for the advanced student. . . . , A short theoretical introduction precedes the detailed preparations. . . , .The textbook is intended to meet the requirements of the student throughout the whole of his training. . . . It will also provide an introduction to research methods in organic chemistry and, it is hoped, may serve as an intermediate reference book for practising chemists.” Here, with the notable exception of quantitative organic analysis, is a one-package presentation of laboratory work in organic chemisEdProceedings of the Society for Experimental Stress Analysis. try on all levels. As a teaching instrument, however, it may not find ited by C. Lipson and W .AM.Murray.Vol. \’, No. 2. Addisonwide use in our American schools, for it embraces much more material Wesley Press, Ino., Cambridge 42, Mass. Price $6. than can be presented in any ordinary laboratory course. Chapters I and I1 (230 pages) cover the “Theory of General Technique” and “Experimental Technique.” Preparations and reactions begin on page 231 (Chapter 11) and conclude on page 887 (end of Chapter X ) . Qualitative organic analysis merits only 66 pages “Methods in Medical Research,” a series of annual volumes de(Chapter XI), although the previous chapters feature tables of physivoted to methods and techniques, is to be published by the Year cal properties and assorted diagnostic reactions useful for identificaBook Publishers, Inc., Chicago, Ill. The Governing Board is conition. The Appendix, entitled “Literature of Organic Chemistry,” posed of Irvine H. Page, A. C. Ivy, Colin >I RlacLeod, . Carl I’. includes information on preparation of palladium catalysts, periodir Schmidt, Eugene .4.Stead, and David L. Thomson. Volume I, undw acid in qualitative organic analysis, etc. The index is ample. the editorship of Van R. Potter, Cniversity of Wisconsin, was availThe preparations are very numerous and appear to be well chosen. able in May 1948,and succeeding books are due every January. In nearly every instance the detailed example is followed by a number Contents of Volume I include: “Assay of .Intibiotics,” by Henry of “cognate preparations.” Thus the directions for making n-butyl Welch; “Circulation,” by Harold D. Green: “Selected Methods in iodide by the phosphorus-iodine method are followed by brief inGastroenterologic Research,” by .4, C . Ivy; and ”C:ellular Respirastructions for making thirteen other iodides in the same general n-ay. tion,” by S’an R. Potter. In a few instances the recommended procedure is not the best available. For example, the preparation of dimethylethynylcarbinol (p. 454) employs the sodamide method rather than the sodium acetylide which gives better yields, is much less hazardous, and can be adapted to a larger scale. The paper is of good quality, the printing is excellent, and there are remarkably few typographical errors. . 4 regrettable feature is that citations to the original literature are not given, although there are numerous references to firms supplying special apparatus and chemicals. Vogel’s textbook n-ill prove a rich source of information for graduate students and other bench workers in organic chemistry. I t should be available in every library that claims to serve their needs. SIR: G. F. HENXIOX The type of apparatus discusbed by Snell (g), was described by the writer in March 1912 (1). Although I used this apparatus in 1938, it is so simple and straightforward that I would be surprised to find Cyanogen Compounds, Their Chemistry, Detection, and Estimation. that I was the first to utilize it. This communication is not t o H. E. Williams. 2nd ed. xvi -I- 443 pages. Longmans, Green claim priority but to point out two details that may be of interest. and Co., 55 E‘ifth Ave., New York 3, N. Y., 1948. Price, $10.50. -4s will be seen from Figure 2 ( 1 )reproduced here, the simple siphon shown in Snell’s diagram is slightly modified (see B ) . Owing to the vacuum created at the top of the siphon. air bubbles tend to form Since 1915 those engaged in the field of cyanogen compounds have there and break the siphon action. I, therefore, included an air trap in turned to Williams when confronted with a problem. For some years the form of an inverted funnel with two inlets at the bottom and an the book was inadequate, but now the second edition has appeared in modified and greatly expanded form. The new edition has omitted outlet at the top, the latter closed by a rubber tube and a clip. By
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Methods in Medical Research
Constant level Control for Water Baths
V O L U M E 20, NO. 6, J U N E 1 9 4 8
593 The second item of interest is the siphon system, FMKG. It was necessary in the water bath concerned to add cold water continuously t o the bath (for the purpose of maintaining constant temperatures below room temperature). In avoiding flooding, this second siphon system was effective and worked without attention for several years. It consists of large-diameter pipe, F X (1-inch iron pipe was used), one limb of which dips into the bath at the level t o be controlled and the second into the water seal, G. Water vacuum pump K ran continuously and thus each time the level in the bath rose to a predetermined point the siphon would automatically start and empty the excess water. The function of the pump v a s simply to start the siphon; its capacity was too small for maintaining a constant level. Only two points have to be remembered in utilizing this system: The capacity of the siphon tube should be larger than the input of the water into the bath, and the difference in height between the constant level and the top of the siphon should be smaller than the difference in height between M and the level in the liquid seal, G .
Figure 2 ( 1 )
(1) Nissan, -4.H., J . Inst. PetroZeum, 28, No. 219. 41 (1942). (2) Snell, C. A., ANAL.CHEM.,20, 186 (1948).
A . H. NISSLN this means the apparatus was found to function without a break for several months at a time; by applying suction to the rubber tube the siphon can also he easily started without dismantling the unit.
Bowater Paper Corp., Ltd., Xorthfleet, Gravesend, Kent, England
Figure 3.
Orthographic Projections of Typical Crystal of p-3Iethyl Aminophenol Sulfate
6. p-Methyl Aminophenol Sulfate (Metol, Elon) Figure 1 (lower). Crystals of p-Methyl iminophenol Sulfate from Water on \Iicroscope Slide. Figure 2 (upper). Crystals of p-Aminoazobenzene from Thymol on IPIicroscope Slide
Crystals of p-methyl aminophenol sulfate suitable for microscopic investigation can be obtained from aqueous solution on a microscope slide. Crystals for x-ray diffraction a n d goniometry can be prepared by slow cooling of aqueous solutions. CRYSTAL MORPHOLOGY (determined and checked by W. C. ?\ICCrone and J. W. Cook).
