NOVEMBER. 1959
601
The author is most successful in presenting the physical aspects of organic chemistry. The student is immediately introduced to the concept of molecular models. The development of the resonance theory is well done despite several inoorreot examples of its application; e. g., tautomeric structures of pyrazole are descrihed as resonance structures. The treatments of refraction, polarization, magnetic susceptibility, and other phenomena not usually included in introductory texts are clear and succinct. The treatment of chemical reactions is conventional. Resonance structures are used in the interpretation of reaction mechanisms. This presentation, however, oontains a number of errors of fact and/or interpretation whichindicate that the author has lost pace with the subject. The reaction sequences proposed, for example, far ester condensation and for the base-catalyzed bromination of ketones are wrong in detail; lithium hydride (instead af lithium aluminum hydride) is described as a ketonereducing agent. Because of its scope this hook should find a place particularly in the training of students still a t an early stage. It should be used, however, only in conjunction with a course of lectures to fill in dehil and to correct errors where required. The price is slightly high hut not outrageous. l N D R E W STREITWIESER, JR
Umvsnamr OP CALIFORNIA B e n m ~ ~ CAL~FORNIA r,
0
MICHAEL TSWElT'S FIRST PAPER ON CHROMATOGRAPHY
G.Hesse and H. W e 2 M. Woelm, Eschwege, Germany, 1954. 35 pp. 2 illustrations. 15 X 20.5 cm. Paper bound. $2. Tins little brochure is divided into three parts: an English tranalation of Tswett's Russian paper: "On a New Category of Adsorption Phenomena and their Application to Biochemical Andysis," published in the Proceedings of the Warsaw Society of Natural Sciences for 1903 (18 pp.); notes on this paper by Hesse and Weil (4 pp.); and notes on Tswett's life (6 pp.). I t contains s short bibliography and two photographs; a reproduction of Tswett's handwritten summary of his academic training and positions, and a snapshot of Tswett a t the age of 40. The latter picture is from DhBrP's excellent biography of Tswett. The translation, the original of which is not readily available, is noteworthy far m m y reasons. I t shows that as early as 1903 Tswett had clear concepts ahout adsorption and its role in analysis, particularly in theextraction, separation, and recovery of the chloroplast pigments. It reveals that Tswett had already ut,ilized his special columnar adsorption procedure and that he was aware of the importance of each step in this procedure; namely, the adsorption of a. small smount of the mixture in a column of finely powdered sorhent forming a narrow initial zone of the sorbed suhstiLnces, the resolution of these sorbed substances by washing with fresh solvent, and the recovery of the separated substances from successive portions of the percolate. I t also discloses that Tswett had not yet proposed the now widely accepted "chromatographic methods" for thin technique and "development of the chromatogram" for the washing of the sorhed substances with fresh solvent. It shows that Tswett had examined oolorless suhstnnces with his method even though his subsequent terminology implied that the method was especially
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