128 



SCIENCE. 



[Vol. X. No. 240 



school. Reading of this sort is greatly needed in all branches of 

 science, and nowhere more than in meteorology. Look, for exam- 

 ple, at the account given of the effects of melting ice and freezing 

 water on the temperature of the adjacent air. The effects appear 

 either in time alone, or in both time and place. When lakes freeze, 

 they retard the early winter fall of temperature, and when they melt 

 they retard the spring warming by an equal amount : this effect is 

 constant in place, but varies in time. On the other hand, when snow 

 falls, the liberation of energy in its freezing affects the temperature 

 of the air at some distance above the earth's surface, making it 

 warmer than it would have been if condensation had not taken 

 place ; but the same snow, melting afterwards on the ground, keeps 

 the air there from warming as much or as soon as it would had the 

 snow been absent. Here, then, is an effect that varies in place as 

 well as in time. It is like carrying ice from New England to India : 

 if this once famous industry had been extensive enough, it would 

 have raised our mean temperature, and lowered that of the torrid 

 zone where the ice melted. 



The second volume of the work is given to a general geographic 

 account of climate. Here a comparison naturally arises with 

 Hann's ' Klimatologie,' that appeared a few years ago. The sub- 

 jects treated are identical ; the difference is only in the plan of 

 treatment and in degree of emphasis given to one part or another 

 by the two authors. Dr. Hann made free use of original accounts 

 by travellers and foreign observers, and inserted abstracts of their 

 writings in smaller type, after presenting his own general state- 

 ments ; he also included the various climatic tables in the text, 

 alongside of the paragraphs that they illustrate. Dr. Woeikof re- 

 duces the records that he consults to common form, and postpones 

 all tables to the end of the book, where they appear with numerous 

 diagrams that have small representation in Dr. Hann's book. 

 Preference between two methods such as these is probably d matter 

 of taste, my own being for that followed by the Austrian author ; 

 but the other will doubtless find equal approval. The absence of 

 sufficient reference to earlier authors makes both books less useful 

 than they might have been ; but the insertion of the references would 

 have materially increased the size of the volumes, already large, 

 and I believe it was for this reason that they were omitted. 



The duplication caused by the almost simultaneous appearance 

 of these two books on one subject can only be regarded as a great 

 advantage. They were independently prepared by leading special- 

 ists ; and the careful reader, who wishes to think as well as to 

 quote, will gain a solid, stereoscopic comprehension of the subject 

 by approaching it from these two slightly different points of view. 



Foods and Food Adulterants. Part I. Dairy Products. (U. S. 

 Dept. Agric, Bull. No. 13.) Washington, Government. 8°. 

 This bulletin, which has been prepared by H. W. Wiley, chemist, 

 is devoted chiefly to a discussion of the best methods of detecting 

 the adulteration of dairy-products, that of butter being treated with 

 greater detail than any other. During the past year the division of 

 chemistry has been supplied with apparatus for photo-micography, 

 and most of the illustrations, twenty-four in number, are the work of 

 the division. Great benefit has been derived from this method of fix- 

 ing the photographic appearance of the crystalline character of butter 

 and butter substitutes. The illustrations show the crystalline ap- 

 pearances of butter, beef-fat, lard, butterine. and oleomargarine, and 

 are well executed. The bulletin contains the text of the act of 1886, 

 passed by Congress, defining butter, and imposing a tax upon, and 

 regulating the manufacture, sale, importation, and exportation of, 

 oleomargarine ; also a detailed histoiy of artificial butter from its first 

 manufacture by M^ge-Mouridz, in 1870, to the present time. The 

 writer of the bulletin believes, that, while a great deal of artificial 

 butter has been thrown upon the market, that has been carelessly 

 made, and therefore harmful to the health, still a butter substitute, 

 made carefully out of the fat of a perfectly healthy bullock or swine, 

 is not prejudicial to health. This opinion is supported by quota- 

 tions from the leading authorities, such as Professors Morton, 

 Chandler, Barker, and others. The best methods of butter and 

 milk analysis are described in detail, both microscopical and chem-. 

 ical. Other bulletins are being prepared, and will soon be issued, 

 treating of condiments, sugar, sirup and honey, drinks and canned 

 goods, flour and meal, tea and coffee, and baking-powders. 



Milton's Paradise Lost. Books I. and II. Ed. with introduction 

 and notes, by M. Macmillan. New York, Macmillan. 16°. 

 The difficulties of Milton's works are so great, owing to the 

 Latinized structure of his style and his many learned allusions, that 

 they require a commentary almost as much as the ancient classics 

 do. Nor have our scholars neglected to provide such helps ; yet 

 for school purposes most of them leave much to be desired. The 

 little book before us is one of the best works of the kind that we 

 have seen, and will help to make the reading of Milton both easier 

 and pleasanter. It is confined to the first two books of ' Paradise 

 Lost,' which the editor rightly considers the grandest portion of 

 Milton's works. The notes are accurate and very exhaustive, as 

 may be seen from the fact that they fill eighty-four pages of the 

 volume, while the text fills only fifty-four. Almost every thing is 

 explained in them that a student would need to have explained, and 

 the explanations are simple and clear. An introduction of moderate 

 length gives an account of the conception and composition of 

 ' Paradise Lost,' together with some judicious criticisms on the 

 poem. The book may be heartily commended for educational use. 



Schiller's Wilhelm Tell. With Introduction and Notes by G. E. 



Fasnacht. London, Macmillan. 24°. 

 Schiller's Walleiistein. Part I. Das Lager. With Introduction 



and Notes by H. B. Cotterill. London, Macmillan. 24°. 

 Messrs. Macmillan & Co. have, in the two books named 

 above, made valuable additions to their Foreign School Classics 

 series. The Wallenstein is preceded by a well-written historical 

 sketch of the origin and character of the thirty-years' war. The 

 difficulties in reading Wilhelm Tell do not lie in Schiller's style and 

 diction. These are throughout transparently clear. Not so the 

 subject-matter. The reader's progress is delayed at almost every 

 step by historical allusions, provincialisms, topographical and 

 meteorological terms, for the elucidation of which even the ad- 

 vanced student needs to have a complete cyclopedia at his elbow. 

 All this reference-hunting involves a great waste of time, and this 

 little edition of the work has been edited with the view to placing 

 these side-lights at the disposal of the reader. 



Higher Algebra. By H. S. Hall and S. R. Knight. London, 

 Macmillan. 16°. 

 The present work is a sequel to the author's ' Elementary 

 Algebra for Schools.' The first few chapters are devoted to a 

 fuller discussion of ratio, proportion, variation, and the progressions, 

 which in the former work were treated in an elementary manner. 

 The discussion of convergency and divergency of series always pre- 

 sents great difficulty to the student. To render this the more in- 

 telligible, the authors have introduced a short chapter on limiting 

 values and vanishing fractions. In the chapter on summation of 

 series they have laid much stress on the method of differences and 

 its wide and important applications. Permutations and combina- 

 tions and the theory of probability have received due attention, also 

 the theory of determinants and their applications. The last chapter 

 contains all the most useful propositions in the theory of equations 

 suitable for a first reading. 



Naturae Veritas. By GEORGE M. Minchin. London, Mac- 

 millan. 16°. 



We learn from the author's preface that in this poem he has re- 

 lated certain things, which, in a temporary absence from this earth, 

 he received from a being who, having completed the change of ex- 

 istence, had attained to a knowledge of the universe far transcending 

 the capacity of man. The poem is descriptive of the author's sup- 

 posed stellar visits in quest of information, which should lay at rest 

 his doubts in regard to the dissipation of energy. Unfortunately 

 the journey was without result. 



The 0-d!e}is College Course of Practical Organic Cheinistiy. By 

 J. B. Cohen. London, Macmillan. 16°. 



This little book on organic chemistry will be received with favor, 

 doubtless, and has already received the high indorsement of Prof, 

 Henry E. Roscoe and Prof. C. Schorlemmer. Any course of prac- 

 tical organic chemistry leading up to original work must mainly 

 consist in a careful preparation of a well-selected series of organic 

 compounds. Dr. Julius Cohen has in this little book collected such 



