ter by the boiling-point method using a 50-cc. side-arm flask. The same corrections are presumably to be applied to boiling points and melting points taken in flasks of other shapes and sizes. No auxiliary thermometer is used, and the discussion gives the impression that the average temperature of the exposed stem is the same as room temperature. No mention is made of shortscale total-immersion thermometen. It is in fact stated that to secure total immersion is "obviously impractical." This treatment of the important matter of corrected thermometric readings is not consistent, in the opinion of the reviewer, with the "vigorous protest" lodged in the preface "against the prevalent practice of cluttering up the chemical literature with 'uncorrected' melting and boiling pointsfigures without any great significance, which could just as well have been corrected and presented in the literature as reliable data." In the directions for the melting-point determination the reference U N ~ B X S IOF PIMAII~LAWD COLLBOE Pdm, MARYLAND to the temperature "at which melting starts" will probably be misinterpreted by many students. The definition of the melting point is followed by an account of the capillary tube method, the AN INTRODUCIION M TA& PRBP~IMTION AND IDENTWICATION inference being that this procedure determines the true melting oa O~onlvrcCOMPOUNDS. R. D. Cogkill and J . M. Sturlcvont, point as stated in the definition. The section on laboratory Yale University. McGraw-Hill Book Co., New York City, operations includes no mention of methods used for drying or1936. xiii 226 pp. 24 figs. 14 X 20 cm. $1.75. ganic solids. The preparative section describes forty-two experiments, of This manual represents an attempt to include in one year's laboratory work the main features of the usual preparative which "only a fraction can usually be included in any course." course and of the less usual but highly desirable course in quali- The list of experiments covers the usual ground in satisfactory tative organic analysis. To make this possible in practice "the manner, illustrating the more important reactions and methods. student makes only half as many preparations as formerly, the To perform only a fraction of the experiments, however, might remaining time being devoted to a form of qualitative organic give the student a decidedly limited acquaintance with preparaanalysis." The results of this method of instruction in the tive "techniques." Several of the preparations may be welcomed as desirable laboratory of the authors are described as "very gratifying." The bwk is in two parts: Part I, preparations, and Part 11, new student experiments, e. g., ethyl resorcinol and p-bromophenidentification of organic compounds. The preparative part oc- acyl bromide. The number of virtual duplicates seems high for cupies one hundred seventeen pages, distributed thus: general so restricted a list, but this feature will permit a wider range of instructions, nine pages, discussion of important laboratory opera- choices while affording all members of a class the same essential tions, forty-one pages, and directions for preparations, siaty- experiences. A number of experiments require distillation seven pages. The section on qualitative analysis occupies under reduced pressure. Liquid bromine is used in at least four ninety-two pages. I t is followed by two appendixes, giving experiments and gaseous chlorine in two, hut the student, exatomic weights, densities of some solutions, and a list of reagents posed to these hazards, is instructed to discard his trace of cufor the qualitative work. There are two indexes, one for com- prous acetylide as "dangerously explosive" and is thus denied the pounds made, used, or identified in the course, and the other a pleasure of exploding it. There is no experiment an the carbosubject index. The first is incomplete with respect to a number hydrates, none on fractional distillation, and no example of a hydrocarbon synthesis. of compounds listed in the tables of derivatives. Each experiment is preceded by a statement regarding the The chapter on "Important Laboratory Operations" discusses distillation, filtration, crystallization, determination of melting method to be used, or alternative methods. These sections are and boiling point, washing and drying of liquid compounds, and usually very brief, with the first sentence in many cases conveyextraction with immiscible solvents, and gives directions far puri- ing the information that the method is important, common, fication of some common solvents, including the drying of alcohol typical, or convenient. No tests are applied to the compounds by sodium and ethyl phthalate. Directions are given for the prepared to verify their chemical characteristics, although in the laboratory preparation of hydrogen chloride, ammonia, carbon present manual such tests would seem to be more than ordinarily dioxide, and hydrogen sulfide. Other needed gases (chlorine, helpful, as an approach to the analytical work. Each experisulfur dioxide, oxygen, hydrogen, nitrogen) are to be provided in ment is followed by a number of well-chosen questions, to be r.,1inasrc answered in the laboratory notebook. , -. In the experiment an acetyl chloride the compound P(OC0Among the comments of a critical nature suggested by a rmcling of thiv section are the following. The use of noritc is specified CH& is stated to be a typical by-product, but is not among the Am. Chem. Soc., 34,492 for the "removal of soluble im~urities."with no mention of de- products revealed in Brooks's study [I. colorization. I t would seem-better to refer to decolorizing (1912)l of the reactions between acetic acid and phosphorus tricarbon, naming norite as one of the available brands. Direc- chloride. In the experiments on preparation of ethyl bromide tions for the washing of crystals an a suction filter leave the no mention is made of ether as a by-product. The apparatus student free to add the wash-liquid with the suction on. The shown for preparation of ethylene and that for ether both have purification of acids and bases by dissolving in water as their rubber connections inside the reaction flask. "Final purificasalts, treating with d~olarizingcarbon, and then reprecipitating, tion" of acetamide is effected hy addition of ether to the molten crude product, all flames within ten feet being extinguished! is referred to as renystalliaatiou. The presentation of the subject of stem corrections in melting- Acetanilide is made by acetylatian with acetic anhydride in and boiling-point determinations may be justified on the ground water, and the student is left to infer that the other acetylating that the degree of accuracy sought is not high, but scarcely on agents mentioned in the introductory paragraph (acetyl chlodidactic or scientific grounds. The usual formula far the cal- ride, acetic acid, ketene) could be used in a similar manner. No culation of the stem correction is given, with a curve which mention of the usual method of acetylatian appears until it is shows the magnitude of the corrections from 50- to 300°, the given in the qualitative part for preparation of acetyl-derivatives average temperature of the exposed stem being in some unen- of amines. The diazo-reaction is well represented by four experiplained way kept a t 25' through the whole temperature range. ments. There is one Grignard synthesis, and opportunity for Bath are then ignored, and a curve for the composite stem and other applications in the qualitative section. Glycine, made calibration corrections is empirically obtained for the thermome- from chloroacetic acid, is isolated hy the old copper glycine
compounds. Part IV is concerned with tautomerism, rearrangements.. dves. . . and stereoisomerism under the headine of "Soecial Results of Certain Structures," while Part \'is dwoted to "Some lmponant Plant and Animal Products" (carbohydrates. fats, prot~ins,and miwdlaneous products). A brief appendix contains a discussion of the identificationof organic compounds. We believe that the acceptance which this hook receives will be determined largely by whether or not prospective users believe with Professor Desha that the arrangement of subject matter outlined above is desirabie. for the hook is well written, the treatment of subject is quite adequate, and the choice of material well made. The tent is practically free from typagraphical errors, and print, paper, and binding are of high quality. NATHAN L. DRAKE
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