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Standards and tests for reagent and c.p. chemicals
684
BOOK R~v,Ews. BOOK
[J. F. I.
REVIEWS.
CHEMICAL ENGINEERING CATALOG. Twelfth annual edition, II6o pages, illustrated, quarto. New York, The Chemical Catalog Company, Inc., I927. Prices adjusted to special conditions as indicated in the volume. This publication has been noticed as it appeared in the issues of the JOURNAL and it is necessary here only to record that the present edition maintains the character of the work as established in its earlier publications and constitutes a very valuable summary of the chemical engineering manufacturing in this country. The classified directory has been further enlarged and contains the listings of more than 2ooo manufacturers. Its use to those engaged in purchasing the materials of chemical engineering is very great and the manner in which the publishers keep in touch with those who use the book is highly commendable. The information bureau maintained by the publishers for many years has been doing excellent service to its customers. More than 24oo books are listed in the technical and scientific books section. Information is also given concerning the American Chemical Society's Monographs. The book is printed in excellent form and very liberally illustrated. HENRY LEFFMANN. STANDARDS AND TESTS FOR REAGENT AND C.P. CHEMICALS. By Benjamin L. Murray. Second edition, revised and enlarged, xiii-56o pages, 8vo, cloth. New York, D. Van Nostrand Company, Inc., i927. Price, $5One of the most important points in chemical analysis is to be assured that the reagents are exactly what they are intended to be. A very large amount of error has occurred in consequence of overlooked impurities. Sometimes such condition may result to the advancement of science. Such is the case in the test for arsenic suggested by Reinsch. He was experimenting on the action of hydrochloric acid on copper and obtained a very distinct deposit upon the metal. It appeared, however, that his hydrochloric acid was impure, containing a notable amount of arsenic and thus he was led to discover a reaction with this important element and with a number of others also of importance. Reinsch's test thus became to be one of our most important preliminary tests in toxicology. One wonders when this procedure would have been discovered if Reinsch had had a pure acid for his experiment. It is also generally known that the test which Kekul~ devised for benzene is really due to the presence of a sulphur compound originally unsuspected. There was much laxity in earlier years in the preparation of reagents and the term c.p. covered some sins, being often merely indicative of an approximate purity. The progress of applied chemistry, however, steadily increased the necessity of precision both as to the detection of substances and their determination. Within a comparatively recent period, therefore, there have grown up two well-developed systems of controlling chemical analysis: The establishment of standard methods and the manufacture of analyzed reagents. The work in hand is a second edition and the preparation of it has involved the revision and improvement of the standards and tests for reagents, which was the only feature of the first edition, and the introduction of considerable
NOV., I927 .]
BOOK REVIEWS.
685
new material for pure chemicals. The modifications of the methods of testing are not very numerous, but they have been obtained by inquiry among the users of the book. Standards of purity and methods for testing over 2oo c.p. chemicals have been introduced. The book represents a very considerable extension of the material that was first presented by Krauch in I87O. As noted above, the author in the preface refers to a lack of agreement between consumers, dealers and manufacturers as to what the expression c.p. means and the author has aimed to secure and present information which may serve to eliminate these confusions. The standards set up are essentially practical, that is, they do not aim at absolute purity but to secure tests which will give to each worker the reagents that are adapted to the problems in hand. The descriptions are comprehensive and in full detail and the book therefore offers to the practical chemist a means of checking up all the materials which are used in analytic routine. HENleY LEFFMANN. MODERN ECLIPSE PROBLEMS, being the Halley Lecture delivered oi1 20 May, 1927, with notes for the observation of the eclipse of 29 June, I927. By F. J. M. Stratton, D.S.O., M.A., Fellow of Gonville and Caius College, Cambridge. 34 pages, illustrations, 8vo, paper. New York, Oxford University Press, American Branch, I927. Price, $.85. Eclipses have excited the wonder and even the fear of mankind since the earliest period of recorded history. It is greatly to be regretted that the ancient philosophers did not make exact records of the time and places of eclipses in their relation to human events, for modern historians would have a most excellent method of checking up chronologic data by this aid. Here and there we have notes of important eclipses, but it appears from the number that must have occurred that but a scant record has been transmitted. As merely a side issue, it is worth noting that the appearances of comets have been occasionally recorded, and it is fortunate that a considerable number of returns of Halley's Comet are now knox~na and accurately dated. In honor of Halley a lecture is now delivered and the present pamphlet, as is stated, refers to the work done in connection with the eclipse of last May. It appears from the introduction that only once in the last thousand years has the belt of totality of a solar eclipse passed across Oxford (in I7r5). W e may contrast the imperfect methods of observation of eclipses for several thousand years up to recent times when the spectroscope and the camera with other special instruments enable far more information to be obtained. We have now indeed through the motion picture method the ability to reproduce the phenomena of the eclipse to every one and everywhere. The present pamphlet furnishes information on many points concerning this recent eclipse visible in England and is illustrated with photographs of various phases. One photograph shows the stars whose displacement verified the theory of relativity. This is an abstruse subject but is part of the data that have been accumulated. As the author remarks, the attitude of civilized mankind toward eclipses has ceased to have any element of superstition or fear and eclipses of the sun have become important as throwing light upon certain problems in physical astronomy. H E N R'~" L E F F M A N N .
BOOK R~v,Ews. BOOK
[J. F. I.
REVIEWS.
CHEMICAL ENGINEERING CATALOG. Twelfth annual edition, II6o pages, illustrated, quarto. New York, The Chemical Catalog Company, Inc., I927. Prices adjusted to special conditions as indicated in the volume. This publication has been noticed as it appeared in the issues of the JOURNAL and it is necessary here only to record that the present edition maintains the character of the work as established in its earlier publications and constitutes a very valuable summary of the chemical engineering manufacturing in this country. The classified directory has been further enlarged and contains the listings of more than 2ooo manufacturers. Its use to those engaged in purchasing the materials of chemical engineering is very great and the manner in which the publishers keep in touch with those who use the book is highly commendable. The information bureau maintained by the publishers for many years has been doing excellent service to its customers. More than 24oo books are listed in the technical and scientific books section. Information is also given concerning the American Chemical Society's Monographs. The book is printed in excellent form and very liberally illustrated. HENRY LEFFMANN. STANDARDS AND TESTS FOR REAGENT AND C.P. CHEMICALS. By Benjamin L. Murray. Second edition, revised and enlarged, xiii-56o pages, 8vo, cloth. New York, D. Van Nostrand Company, Inc., i927. Price, $5One of the most important points in chemical analysis is to be assured that the reagents are exactly what they are intended to be. A very large amount of error has occurred in consequence of overlooked impurities. Sometimes such condition may result to the advancement of science. Such is the case in the test for arsenic suggested by Reinsch. He was experimenting on the action of hydrochloric acid on copper and obtained a very distinct deposit upon the metal. It appeared, however, that his hydrochloric acid was impure, containing a notable amount of arsenic and thus he was led to discover a reaction with this important element and with a number of others also of importance. Reinsch's test thus became to be one of our most important preliminary tests in toxicology. One wonders when this procedure would have been discovered if Reinsch had had a pure acid for his experiment. It is also generally known that the test which Kekul~ devised for benzene is really due to the presence of a sulphur compound originally unsuspected. There was much laxity in earlier years in the preparation of reagents and the term c.p. covered some sins, being often merely indicative of an approximate purity. The progress of applied chemistry, however, steadily increased the necessity of precision both as to the detection of substances and their determination. Within a comparatively recent period, therefore, there have grown up two well-developed systems of controlling chemical analysis: The establishment of standard methods and the manufacture of analyzed reagents. The work in hand is a second edition and the preparation of it has involved the revision and improvement of the standards and tests for reagents, which was the only feature of the first edition, and the introduction of considerable
NOV., I927 .]
BOOK REVIEWS.
685
new material for pure chemicals. The modifications of the methods of testing are not very numerous, but they have been obtained by inquiry among the users of the book. Standards of purity and methods for testing over 2oo c.p. chemicals have been introduced. The book represents a very considerable extension of the material that was first presented by Krauch in I87O. As noted above, the author in the preface refers to a lack of agreement between consumers, dealers and manufacturers as to what the expression c.p. means and the author has aimed to secure and present information which may serve to eliminate these confusions. The standards set up are essentially practical, that is, they do not aim at absolute purity but to secure tests which will give to each worker the reagents that are adapted to the problems in hand. The descriptions are comprehensive and in full detail and the book therefore offers to the practical chemist a means of checking up all the materials which are used in analytic routine. HENleY LEFFMANN. MODERN ECLIPSE PROBLEMS, being the Halley Lecture delivered oi1 20 May, 1927, with notes for the observation of the eclipse of 29 June, I927. By F. J. M. Stratton, D.S.O., M.A., Fellow of Gonville and Caius College, Cambridge. 34 pages, illustrations, 8vo, paper. New York, Oxford University Press, American Branch, I927. Price, $.85. Eclipses have excited the wonder and even the fear of mankind since the earliest period of recorded history. It is greatly to be regretted that the ancient philosophers did not make exact records of the time and places of eclipses in their relation to human events, for modern historians would have a most excellent method of checking up chronologic data by this aid. Here and there we have notes of important eclipses, but it appears from the number that must have occurred that but a scant record has been transmitted. As merely a side issue, it is worth noting that the appearances of comets have been occasionally recorded, and it is fortunate that a considerable number of returns of Halley's Comet are now knox~na and accurately dated. In honor of Halley a lecture is now delivered and the present pamphlet, as is stated, refers to the work done in connection with the eclipse of last May. It appears from the introduction that only once in the last thousand years has the belt of totality of a solar eclipse passed across Oxford (in I7r5). W e may contrast the imperfect methods of observation of eclipses for several thousand years up to recent times when the spectroscope and the camera with other special instruments enable far more information to be obtained. We have now indeed through the motion picture method the ability to reproduce the phenomena of the eclipse to every one and everywhere. The present pamphlet furnishes information on many points concerning this recent eclipse visible in England and is illustrated with photographs of various phases. One photograph shows the stars whose displacement verified the theory of relativity. This is an abstruse subject but is part of the data that have been accumulated. As the author remarks, the attitude of civilized mankind toward eclipses has ceased to have any element of superstition or fear and eclipses of the sun have become important as throwing light upon certain problems in physical astronomy. H E N R'~" L E F F M A N N .