March io, 1893.] 



SCIENCE. 



137 



as the object, and, second, because of the wrong and foolish 

 method of conversation employed — not necessarily by the child's 

 parents — when talking to him. Such examples as "Baby kiss 

 mamma," " Does Freddie love his auntie?" "Is little Mary cold ?" 

 •etc., can hardly lead to an early conception of correct verbal ex- 

 pression. Howard Liuenthal, M.D. 

 New York, 43 East 29th Street, March 6. 



Solidungulate Pigs. 



The "mule footed hogs" inquired about by Mr. Jno H. Frick. in 

 Science of Feb. 24, p. 107, are described and figured in my article 

 entitled "On a Breed of Solid-Hoofed Pigs Apparently Estab- 

 lished in Texas," Bull. U. S. Geol. and Geogr. Surv. Terr., Vol. 

 IV., No. 1, Teb. 5. 1878. p. 295. Elliott Coues. 



Smithsonion Institution, Washiugton, D. C, March 1. 



BOOK-EEVIBWS. 



•Original Papers on Dynamo Machinery and Allied Subjects. By 

 John Hopkinson, M.A., D.Sc, F.R.S. New York, W. J. 

 Johnston Company. 



This volume is a collection of the papers on electro-technical 

 subjects which Dr. Hopkinson has published at various times 

 during the last fourteen years. 



It will be unnecessary to speak of the great value of these 

 papers, for a number of them have passed into the text-books and 

 form a part of the education of every technical student, and there 

 is probably not an electrician in the country who has not found 

 himself obliged to obtain the greater part of the remainder in 

 some form or other. But a book of clippings from engineering 

 journals is never so satisfactory as a bound volume, and the elec- 

 trical profession will accord a warm welcome to this little book, 

 the more so as it contains several papers which have hitherto been 

 difficult to obtain. Of the eleven papers here collected, five are 

 on electric lighting and dynamo-electric machinery, two on trans- 

 formers and transformer tests, two on theory of alternating cur- 

 rents, one on an electrostatic effect in conductors carrying alter- 

 nating currents, and one on electric light-houses. The first five 

 contain the " epoch making" work on characteristic curves, and 

 on efficiency tests of dynamos. (In passing, it may be noted that 

 the paragraph on page 36, on the use of the characteristic to find 

 the lowest speed at which a machine can be run and yet produce 

 an arc, is given wrongly in Professor S. P. Thompson's "Dynamo- 

 Electric Machinery." page 273.) But to technical readers the 

 most interesting portion will be the papers on alternate currents 

 and transformers, included in which is an account of the recent 

 tests on the Westinghouse transformer, of importance as showing 

 that the old accusation of poor all-day efficiency can no longer 

 be made against the commercial transformer. These treat of the 

 parallel and series running of alternators, the design of trans- 

 formers, the effect of capacity in transformers, the power con- 

 sumed in alternating current arcs, etc. 



The advantage that this book has over the papers as originally 

 printed is the fact that most of the errors and misprints have 

 been corrected. A few yet remain, however. On page 155, 2 ji 

 should read 2 7r; sine 2 iT/T{t + t) should read sin i it / T (t — t); 

 the sign of the solution of the diflferential equation for H should 

 be — instead of -(-. Oh page 157, ey should read 2)-; through 

 the whole of this part of the book H' is printed instead of H. This 

 would be objectionable if intentional, but it seems to be an acci- 

 dent, as on page 179 the dot is used instead of the stroke, but 

 placed wrongly. 



Electricity and Magnetism : Being a Series of Advanced Primers 

 of Electricity. By Edwin J. Houston, A.M. , Professor of Natu- 

 ral Philosophy and Physical Geography in the Central High 

 School of Philadelphia. New York, W. J. Johnston Co. 

 From the jn-eface we learn that this book is meant for the "gen- 

 eral public" and the increased "number of those to whom a 

 knowledge of the laws of electricity has become a necessity of 

 every-day business life." While it is proverbially bard for a 

 specialist to decide what the public want, it may be doubted if 



they will see much to choose between this and the scores of 

 similar books which have been published. It is possible, however, 

 that the name on the title-page may prove an attraction to many. 

 On inspection the book is found to treat of the simpler theoretical 

 principles, technical subjects, such as the dynamo, arc-lamp, etc., 

 taking up about fifty lines out of the three hundred pages which 

 comprise the book. 



As in most books of the class, there are numerous inaccuracies; 

 to mention a few : on page 23 a black surface is stated to be a 

 worse radiator of light than a white one; whereas, of course, the 

 reverse is the case; carbon is given as an exception to the rule 

 that the conducting power of metals decreases with rise of tem- 

 perature; the " conducting power of all alloys or mixtures of dif- 

 ferent metals " is stated to be " very much less than that of any 

 one of the metals of which they are composed," in forgetfulness 

 apparently of the fact that Matthiessen gives a long list of alloys 

 whose conductivity is the mean of their constituents, etc. 



The idea of giving references and extracts from books which 

 should be read by those desiring a fuller knowledge of electricity 

 than can be gained from the primers, can be considered a good 

 one. It may, however, be questioned if the quotation from Pro- 

 fe^isor Ayrton's book, "Practical Electricity," would give a 

 reader the impression that it is a book on electrical laboratory 

 work, and whether there is any necessity of quoting the author's 

 "Electrical Dictionary" and "Physical Geography" so often 

 among the selections from standard works, especially where, as 

 on page 161, under " Extracts from Standard Works," the author 

 quotes his dictionary as quoting Fleming, where the extract 

 could, with no loss, have been made directly from the original. 

 The chapter on Electrical Work is one of the hest in the book, 

 and the unscientific reader can hardly fail to understand the ideas 

 treated of completely. R. A. F. 



Contributions from the Botanical Laboratory of the University of 



Pennsylvania. Vol. I., No. 1. 

 Bulletin of the Scientific Laboratories of Denison University, Gran- 

 ville, Ohio. Vof. VII. 



In these days of enormous multiplication of books, magazines, 

 journals, proceedings of societies, etc., there should always be 

 reason for the establishment of a new serial. The avenues of 

 publication are already so numerous that it is almost impossible 

 to keep track of all. The agricultural experiment stations have 

 vastly increased the amount of literature dealing with scientific 

 results, and the comparatively new departure of universities, in 

 issuing periodical publications, is one rather to be deprecated than 

 encouraged. It would seem farbetter, for example, to do as Colum- 

 bia College in New York, and Harvard University in Cambridge 

 do, that is, to publish articles in established periodicals or scien- 

 tific serials, rather than to originate new ones. Columbia College 

 pubhshes the " Contributions from the Herbarium " in the Trans- 

 actions of the New York Academy of Science, while Harvard 

 University prints " Contributions from the Chemical Laboratory " 

 in the Proceedings of the American Academy of Arts and Sci- 

 ences. 



These remarks are induced partly by the recent appearance of 

 No. 1 of Vol I. of " Contributions from the Botanical Laboratory 

 of the University of Pennsylvania" and Vol. VII. of the "Bulle- 

 tin of the Scientific Laboratory of Denison University." Both of 

 these are creditable publications. The former contains some 

 valuable papers upon Dionoea and other subjects, and the latter is 

 a catalogue of the flowering plants and ferns of Licking County, 

 Ohio. With the Philadelphia Academy, the Franklin Institute, 

 and the American Philosophical Society, all issuing serials in 

 Philadelphia, the raison d'etre for a new serial there does not ap- 

 pear. The case of the Denison University is not quite parallel, 

 but most probably there would be little difficulty in arranging for 

 the publication of such papers in other places. 



In the University of Pennsylvania contributions we have the 

 following papers: " A Monstrous Specimen of Rudbechia hirta," 

 by J. T. Rothrock; "Contributions to the History of Dionoea 

 musciptda," by J. M. McFarlane; "An Abnormal Development 

 of the Inflorescence of Dionoea." by John W. Harshberger; "Man- 

 grove Tannin," by H. Trimble; "Observations on Epigcea re- 



