October 23, 1891.] 



SCIENCE. 



235 



LETTERS TO THE EDITOR. 



*** Correspondents are requested to be as brief as possible. Hie writer's name 

 is in all cases required as proof of good faith. 



On request in aduance, on", hundred copies of the number containing his 

 communication wilt ie furnished free to any correspondent. 



T}te editor wilt be glad to publish any queries consonant with the characttr 

 of the journal. 



Solar Difi'raction Glow, 



A FAINT yet clearly pprceptible diCfractiou ring has appeared 

 around the sun for about a week past. It had a pale purplish 

 tint, and at the outer margin faded into the blue sky by almost 

 imperceptible degrees. The centre was tinted nearly to the sun, 

 and was not so bright and white as was the case in Bishop's ring 

 in 1883-85. The part of the ring at 23* degrees from the sun was 

 little if any brighter than the parts adjacent. The outer margin 

 of the ring reached to 30 degrees, and some days perhaps to 35 

 degrees. The storms of late September and first days of October 

 cleared away and left the deep blue sky without a cloud or even 

 haze. The colored ring could not be definitely recognized till 

 alxjut noon. After that time it grew brighter till sunset, when 

 the part of the ring which remained above the horizon rapidly 

 changed to a most brilliant violet-purple. The illuminated por- 

 tion of the sky at sunset was nearly semi-circular and had a 

 greater diameter than the tinted ring of the afternoon, but where 

 the ring had been perceptible during the day, the twilight tints 

 were most intense. 



These observations were made in the San Juan Mountains in 

 Colorado, at an altitude of 10,800 feet. I observed Bishop's ring 

 for about two years, and this ring is in several respects diflferent 

 from that. G. H. Stone. 



Iroaton, Col., Oct. 13. 



Rain-Making. 



Reasoning from well-established meteorological principles alone, 

 I should say that the probabilities of success in rain-making are 

 quite small. But we have learned that it is hazardous to predict 

 confidently, a priori, what nature may do under untried condi- 

 tions. New principles may be discovered which may modify the 

 operation of those already known. As far as I am informed, re- 

 ports concerning the results of the experiments being made in 

 the South-west are contradictory. And if rain does follow a few 

 explosions there at this season of the year, when rains occur in 

 most portions of the temperate zones, would that settle the ques- 

 tion without dispute? 



It seems to me that the effects following great battles have not 

 been recorded with sufficient care to furnish reliable data. When 

 the air in any region is nearly saturated with moisture, it is rea- 

 sonable to suppose that a violent disturbance in the atmosphere 

 may cause a sufficient condensation to produce rain. But when 

 it is far below saturation, it seems to me that the results must be 

 doubtful until fully established by experiment. Let the experi- 

 ments be made in places where it seldom or never rains — for in- 

 stance, in the Sahara. A series of such experiments would deter- 

 mine the question without doubt. I await results with great 

 interest. Marshall Henshaw. 



AsQherst, Mass , Oct. 14. 



AMONG THE PUBLISHERS 



A BOOK has just been published entitled " The Business of 

 Travel,"' a fifty years' record of progress, by Eraser Rae, giving in 

 detail an account of the origin and growth of the now marvel- 

 lously developed organization of Thomas Cook & Son. To scores 

 of thousands who have made pilgrimages to the Meccas of the 

 world as excursionists, guided, directed, and conserved in all in- 

 terests by this concern, this book, which is packed with informa- 

 tion as to travel in this country, in Europe, and in Eastern lands, 

 will be found not onlj' entertaining but instructive. 



— The Publishers' Weekly says, that, in response to an inquiry, 

 the Assistant Secretary of the Treasury writes the following, 

 which will be of interest to all bookbuyers: " In reply to your let- 

 ter in which you inquire if you can purchase books in England 

 and have them sent to you by mail, I have to inform you that the 

 importation of dutiable articles, which includes dutiable books, is 

 forbidden bv ArticleXl. of the Universal Postal Union Convention, 



and books so imported are subject to seizure. Books printfd ex- 

 clusively in languages other than English, and various othi r books, 

 are exempt from duty under certain provisions of the Free List, Act 

 of Oct. 1, 1890, and such books are not included in the prohibition. 



— John Wiley & Sons have in preparation a "Manual of Min- 

 ing," by Professor M. C. Ihlseng. 



— There has been no book written on Hawaii, or the Sandwich 

 Islands, as many still call them, within the last twenty years. 

 But this silence will soon be broken by Mrs. Helen Mather, who 

 has written an account of "One Summer in Hawaii," which the 

 Cassell Publishing Company will publish. Mrs. Mather's book will 

 undoubtedly turn the attention of many travellers toward this 

 little group of islands in the Pacific. It will be illustrated from 

 photographs and drawings made by Walter McDougall, who has 

 had the pleasure of spending part of the summer in Hawaii. 



— Miss Isabel F. Hapgood has translated a large number of 

 Tolstoy's books, and Miss Isabel F. Hapgood has been journeying 

 in Russia. What more natural than that she should see "Count 

 Tolstoy at Home," and what still more natural than that she 

 should make this the title and subject of a paper in the November 

 Atlantic. Miss Hapgood, although admiring his great gifts, is not 

 a blind adherent of his changeable philosophies. Here is a bit of 

 useful information : the name Tolstoy with the y is the writer's 

 own way of spelling his own name, and not a typographical 

 error. 



— Little, Brown, & Co have just ready the ninth edition of 

 Bartlett's "Familiar Quotations," greatly enlarged, and now rep- 

 resenting eight hundred and fifty authors and twelve thousand 

 new lines of index, making the volume one-third larger than the 

 previous edition; and " A Narrative of Events Connected with the 

 Introduction of Sulphuric Ether into Surgical Use," by Richard 

 Manning Hodges, A.M., M.D., formerly of the Massachusetts 

 General Hospital. 



— All teachers who are interested in seeing the best master- 

 pieces of literature put before school children in an attractive and 

 inexpensive form will be gratified to learn that Houghton, Mifflin, 

 & Co. have just issued, as No 51 of their Riverside Literature 

 Series (price, in paper covers, 15 cents), "Rip Van Winkle and 

 other American Essays from Washington Irving's Sketch Book." 

 In addition to "Rip Van Winkle," the book contains the famous 

 "Legend of Sleepy Hollow," " Philip of Pokanoket," introductions 

 and explanatory notes, and a biographical sketch of the author. 

 Early in December, No. 53 of the same series will appear, con- 

 taining " The Voyage and other English Essays from the Sketch 

 Book." 



— The Peruvian traveller and linguist. J. J. von Tschudi, lately 

 deceased, had been successful in collecting almost all the books, 

 pamphlets, and treatises that had ever appeared in the Quichua 

 language, still the most important idiom of that exteiLsive country. 

 Among the few oldest books which he had never been able to see 

 is the grammar of the Dominican priest Domingo de Sancto 

 Thomas, " Arte de la lengua Quichua." The well-known repub- 

 lisher of South American linguistic books. Dr. Julius Platzmann, 

 has been fortunate enough to secure a copy at a pretty steep price, 

 and has now reproduced it in a fac-simile edition, for sale at B. G. 

 Teubner's, Leipzig. It is a neat little sedecimo in small Gothic 

 print, containing a prologo and ninety-six leaves (193 pagas). Old 

 Indian grammars of those times are fashioned after the model of 

 the Latin language, and this one makes no exception. It was the 

 first grammar of the Quichua language, and evinces an uncom- 

 monly thorough study of it. It is dated Valladolid, 1560. The 

 Quichua lexicon of this author is of the same date, and is the first 

 print in which the name "Quichua," which is the name of a Peru- 

 vian trit)e of the Andahuaylas district, has been applied to this 

 language. 



— Messrs. J. B. Lippincott Company announce for early publi- 

 cation the " Life of Benjamin Harris Brewster," by Eugene Cole- 

 man Savidge, M.D. Mr. Brewster took an active and important 

 part in many of the most critical and exciting movements in our 

 recent national history. He knew more or less intimately every 

 American celebrity since the time of Webster and Cay, and his 



