February 21, i8qo. 



SCIENCE. 



1 29 



Aisohtte Measurements in Electricity and Magnetism. By An- 

 drew Gray. 2d ed. London and New York, Macmillan. 

 16°. $1.25. 



The fii-st edition of this work was published in 1884. It con- 

 sisted mainly of papers which had previously been contributed to 

 the columns of Nature by Professor Gray, together with such 

 alterations and additions as he deemed advisable to make in order 

 to render the book more generally useful. While it made no 

 pretensions to being a complete or exhaustive ti-eatise on the 

 subject, it gave, as far as its limits admitted, a clear account of 

 "the present system of absolute units of electi-ical and magnetic 

 measurements, as well as of some methods and instniments by 

 which the system may be applied in theory and in practice. 



Something over a year ago the first volume of a more com^jre- 

 hensive treatise on the subject, by the same author and publishers, 

 made its aiopearance, which, together with the second volume 

 now in preparation, it was intended would supersede the original 

 small work, then out of print. But Professor Gray found that a 

 demand still existed for the original work, or for one similar to 

 it ; and the present edition, amplified and brought down to date, 

 is the I'esult. In it are incorporated a few pai-ts of the lai'ger 

 work, which add much to its value. 



Among the many additions to the present work may be men- 

 tioned a fuller account of the determination of the horizontal 

 component of the earth's magnetic field; a description of Sir 

 William Thomson's standard electrical insti-uments ; a more com- 

 plete ti'eatment of the graduation of instruments ; an extension of 

 the theory of alternating machines, including Dr. Hopkinson's 

 theory of the working of alternators in series and in parallel, and 

 additional information regarding the measurements of activity, 

 etc., in the circuits of alternators; and a chapter on the theory 

 of dimensions of physical quantities. In the last-named chapter 

 the author takes the view that the dimensions of the electi-ic and 

 magnetic inductive capacities should be left undetermined, and 

 regarded as so related as to render the dimensions of every physi- 

 cal quantity the same in the electro-static as in the electi-o- 

 magnetic system of units. 



A Handbook of Florida. Part I. Atlantic Coast. By C. L. 

 Norton. New York, Longmans. 16°. 50 cents. 



We are so accustomed in this country to the most trashy 

 kind of guide-books, that it is positively refreshing to find in 

 this first part of what is to be a guide-book of the whole of 

 Florida a book containing the very information a traveller 

 needs, told in plain, straightforward English. Why the ma- 

 jority of American guide-books are so worthless is not so plain, 

 unless it is that there is, or has been, but little demand for 

 any, not to say the best. But it is certain that the plan of 

 setting the ordinary reportorial talent at work in "writing 

 up" our places of interest does not result in any very intelli- 

 gible descriptions. Mr. Norton's book is a model, and can be 

 commended to those interested, and to those likely to inflict 

 guide-books of another stripe upon the travelling community. 



The whole work is not published as yet, but the other parts 

 are promised to be ready soon. 



AMONG THE PUBLISHERS. 



At this time, when the works of Jean Frangois Millet are 

 being much discussed, readers will be interested in the an- 

 nouncement of two articles upon Millet, his companions and 

 friends. The May Scribner will contain the first of these 

 articles upon tbe artist's life at Barbizon. The author, Mr. T. 

 H. Bartlett, who has been long a resident of Barbizon and an 

 admirer and student of Millet" s work, has incorporated many 

 unpublished letters of Millet, and has furnished a great wealth 

 of new material for -illustrating the articles abundantly. 



— The following extract is taken from a letter written from 

 Cairo, Egypt, recently received from Mr. Henry M. Stanley, 

 about his forthcoming book : ' 'I believe the work will be in two 

 volumes, from 4.50 to 500 pages each. God knows there is 

 matter enough, but I would wish to deal very lightly with the 



whole from Zanzibar to Yambuya, that the book might be of 

 as high interest as the main theme. ... I have six note-books 

 filled with matter extremely interesting. Three long chapters 

 are already written. I have a number of most interesting 

 photographs of scenery, sketches of incidents, scenery, etc. , 

 and maps will be a prominent feature. I hope it will be 

 ready in May." 



— Tbe ninth part of the current series of Edwards's "But- 

 terflies of North America" iBoston, Houghton, Mifilin, & Co.) 

 is fully up to the average standard. The first plate is given 

 up to species of Argynnis, the females of two Western species 

 being for th-e first time figured ; while the early stages of our 

 common Eastern A. aphrodite are admirably illustrated, every 

 stage of the caterpillar having a colored figure. Only tbe 

 earliest stage is given by Scudder. Edwards makes the inter- 

 esting statement that protection is sought at pupation by con- 

 structing a tent, — a feature not before observed in this genus. 

 The second plate illustrates the Southern Satyrus pegala, but 

 only the butterfly ; and the third, Erebia Epipsodea of the Rocky 

 Mountains. Heretofore our knowledge of the transformations 

 of any species of this genus, abundant in parts of Europe, has 

 been most meagre, but here we are treated to,a plate full of 

 exquisite details, leaving nothing to be desired ; and this when 

 the insect had to be obtained from points thousands of miles 

 away, and sent five hundred miles again to the artist. We are 

 equally amazed at the enterprise and the success of the author. 

 Tlie chrysalis was found to pupate in an inclined position, head 

 upward, in a clump of grass whose blades were fastened by a 

 few threads, _ forming a rude kind of cocoon. The spines of the 

 cremaster are without hooks. Illustrations of the transforma- 

 tions of other satyrids are promised in the present volume; and 

 Mr. Edwards hopes to show that this group should be placed at 

 the bottom, and not at the top, of the butterflies, — not an 

 easy task when he has to ignore the fundamental structure of 

 the final stage. This excellent iconography, which has ap- 

 peared at intervals ever since 1868, surpasses in the excellence 

 of its illustrations any heretofore attempted or now publishing; 

 and it is strange indeed that the entomologists of Europe 

 have not been spurred by its excellence to some sort of rivalry 

 in illustrating the histories of their native species. They 

 have nothing which can in any way approach it, and yet the 

 cost of work of this class is far cheaper in Europe than with 

 us. Mr. Edwards's enterprise should be well sustained. 



— According to a circular lately issued by the Geological Sur- 

 vey of Ai-kansas, we learn that an act of the Legislature directs 

 that the reports of the State Geological Survey, with the excep- 

 tion of certain specified copies, shall be sold by the secretary of 

 state at the cost of printing and binding. The reports thus far 

 issued, and their prices, are as follows: "Annual Report for 

 1888, Vol. I., Geology of Western Centi-al Ai-kansas," by mail, 

 one dollar; "Vol. II. South-west Arkansas, " one dollar ; "Vol. 

 III. Coal," seventy-five cents. They may be had by addressicg 

 Hon. B. B. Chism, secretary of state. Little Rock, Ark. Reports 

 are being prepared, and will be issued as soon as possible, on the 

 following topics: 1. Kaolins, clays, and clay shales; 2. Com- 

 plete report on the coal of the State; 3. Manganese: 4. Marbles 

 and limestones ; 5. Novaculites; 6. Crystalline rocks ; 7. Wash- 

 ing-ton County; 8. Crowley's Ridge; 9. Miscellaneous reports. 



— Mention has been made from time to time of the topographi- 

 cal map of Massachusetts, the plan of joint work by the State 

 and the United States Geological Sui-vey, the Grey lock map issued 

 by the Appalachian Mountain Club, and the general map of the 

 State of recent date, all having been described in our columns. 

 Tliere is now to be added a ' • map of the country about Boston, ' ' 

 again issued by the Appalachian Club, a very welcome addition 

 to our local cartogi-aphic material. It is printed from the stones 

 that will be used in the final issue of the map for the State, the 

 scale being 1 : 62, 500, with brown contoui-s every twenty -feet. 

 We are glad to note that it comes from the lithogTaphic estab- 

 lishment of George S. Harris & Sons of Philadelphia ; and from 

 this it may be inferred that the number of houses capable of do- 

 ing this sort of w'ork in our country is increasing, and that the 



