134 THE ANALYST. REVIEWS. A Jfanunl of Organic Clienzisty, Practical ant1 Tlieoretical, for Colleges and Schools. By HUGH CLEMENTS. London: Blackie & Son, 1879. THIS work, despite its somewhat ambitious title, is a, small volume of some 280 pages. A large portion of it is stated to be a reprint from serial papers vhich have appeared in the IGzglish MtcJianic and TVorZtl qf Scieitce, and it is put forward with the object of forming a, ‘‘ test book ” for caildidates preparing for examination.There is one chapter on the (‘ Identification of Organic Substances,” whicli, in its general design and style, is original, and likely to prove useful to a student. This chapter extends to some 46 pages, and the author has evidently taken some pains to make it worthy of reference ; and, notwithstanding some curions and unfortunate errors which occur, he has, on the whole, sncceedecl.A more systematic arrangement mould, however, have improved it. The chapter on ‘( Oils ” would be useful for reference, if the errors, which are scattered through it, were weeded from it. Thus, we are told that linseed contains 20 per cent. of fat, and a few pages further the maximum limit is fixed at 27 per cent.But, having noticed these two chapters, we cannot give a single word of praise to the remainder of the book. Its evident object is to serve as a ‘‘ crib,” and enable a student to snccessfully pass an examination without having really acqnired the lrnowledge which the examinntion was ineniit to test. Nearly 90 pages are occupied with what professes to be a reprint of the papers set in Organic Chemistry at the Science a i d Art May Examinations for the last eleven years, with the correct answers or references to that part of the volume in wliich they may be found.It is obvious that the use of such a ‘ I key ” ns this must be attended with both chemical and moral injury to the student, and must compel the examiners to take far greater heed of the results of practical work than of the replies to questions wliioh may be learned by rote.Another chapter consists of a series of so-called exercises, which are simply a series of quest’ions, some being of the most puerile kind, snch as ‘‘ What organic substances taste acid ? ” sweet ? ” ‘( bitter ? ” “ peculiar ? ” while in others the student is yequested to make a qualitative analysis of the following “ mixtiiws,” among which appear beef, mutton, blood, oranges, urine, coal gas, ink, &c.We fear that Mr. Clements’ loose mode of expression is not calculated to foster habits of nccurncy in those who take his book as a guide. An I ~ i t r o i h c t i o n to Plbarntaceiitical and Jfetlical Cliemistyy (Tliroretical rtnd Descriptive ).By DR. JOHN MUTER, F.C.S. Air I)ttrodztction to Ajtalytica7 CJLemistry (:for Phaiwzaceutical and Meilical Students ). By the same author. Loiidon : Simpkin & &farshall, and BailliAre, Tinddl & Cox. These two volumes constitute the second edition of the author’s Phamacoiitical Clientistry, which has been thus divided, owing to its bnlky proportions, into a book for the laboratory and one for home study. The organic portion has been somewhatTHE ANALYST.135 extended, but otherwise the whole work retains its original scheme of teaching the salts under their respective acidulous radicals instead of following the usual metallic arrange- ment. Tlie practical volume contains iiiter nZiu a new course for the third group in the presence of phosphoric acid.Criticism at our hands is manifestly impossible. Xkeleton Xotes o n Annlyticnl Cheiizistry. London : Churchill, 1870. THESE skeletou notes are extracted from the fifth edition of Dr, Bernay’s 2C’otes for Stzdeuts in Clt.e)nistiy. They form a small and handy volume of about 50 pages. The author has not adopted the tabular form, but presents all the information in ordinary letterpress.The arrangement of the book is good, and by the careful use of four different types reference is very greatly facilitated. It is specially designed for tlie use of medical students, but those who are carryiiig the study of chemistry far beyond the simple requirements of the College of Surgeons, will find it not only a useful pocket companion but reliable for its accuracy.By A. J. BERNAYS. Nitric Xitrogen in Guano. MR. R. R. TATLOCK lias communicated a paper on the above subject to the Newcastle Chemical Society. He points out that by the soda lime process a large portion of tlie nitrogen, which exists in guanos in the form of nitrates, is transformed into ammonia during the combustion, and a considerable error therefore introduced into the analysis.As many natura.1 gumos contain 1 to 2 per cent, of nitrates the error is important even in reference to them, but becomes much more so when guano has been adulterated with nitrate of soda ; since, if a separate determination of the nitrates is made, and no allowance made for the quantity obtained as ammonia, a purchaser would virtually be called upon to pay for the nitric nitrogen twice over.The author has made a number of experimental soda lime combustions, in which amall known quantities of nitrate of liotash were intimately mixed with known organic substances such as starch, albumen, sugar, &c., and then burnt. Prom these experiments he draws the following conclusions :- 1. That using 3 of organic matter (starch) to 1 of nitrate, 45.30 per cent. of the nitric nitrogen caii be obtained. 2. That in no case was the whole of the nitric nitrogen converted into ammonia, the greatest proportion being 97-40 per cent. 3. That the results are somewhat variable, even with the same proportion of tlie ingredients, something always depending on the completeness with which the mixture is made, The author reviews the different methods used for determining Nitric Nitrogen in Guanos, and expresses a strong opinion in favour of Crums’ process, since the results are not affected by the organic matter. He points out, however, the desirability of testing the liberated gas by a warm solution of iron sulphate to prove that it is entirely nitric oxide.