232 



KNOWLEDGE 



[OOVB.K, 1002. 



as a typical insect. Then come full descriptions of some thirty 

 selected common insects of various orders, attention being given 

 to their form, life-history, bionomics, and jiractieal importance, 

 as useful or harmful to the farmer or i^ardcner. This section 

 occupies the greater part of tlie book, and is followed by a short 

 summary of the insect orders and their more important families. 

 Finally, the author gives a section on the " Destruction or 

 Mitigation of Insect Pests,'' placing before the student some 

 general principles to guide him in his economic work and 

 relating in detail the successful struggles of American entomo- 

 logists against the " Gipsy Moth " and the " Fluted Scale." 

 The style of the book is beautifuUy clear, and the facts are set 

 forth so as to attract and fascinate the student. He is led to 

 study an insect practically, and encouraged to look for the 

 reasons of what he observes. The accounts of the life-histories 

 are constantly lighted up with bright flashes of suggestion. 

 " Why," asks the author, " has the female Vapourer Moth no 

 wings ?" He points out that first of all we need to ivsk, " Why 

 insects fly at all" ; and thus we arc led on to a fruitful dis- 

 cussion of the relative importance of the larval and perfect 

 stages in securing the spread of an insect species. Everywhere 

 is pressed home the lesson that the successful mitigation of 

 insect pests depends upon our knowledge of their life relations. 

 The book cannot fail — in the full sense of the words — to educate 

 naturalists. 



In answer to many enquiries, the publishers of Knowledge 

 state that Mr. E. W. Maunder's book, " Astronomy without a 

 Telescope " (which also contains the articles on " Constellation 

 Studies ") will be ready about the middle of October. A large 

 portion of the work has been rewritten. 



BOOKS RECEIVED. 



Elements of the Theori) of the Newtonian Potential Function. By 



B. O. Pcirce, PH.D. (Boston and London : Ciinn & Co.) 128. 

 Beasts of the Field. By William J. Long. (Ginn & Co.) 



Illustrated. 76. 6d. 



Fowls of the Air. By William J. Long. (Ginn & Co.) Illustrated. 

 76. 6d. 



The Common Spiders of the United States. By James H. 

 Emerton. (Ginn & Co. ) 6s. 6d. 



Our Countrt/'s Fishes and How to Know them. By W. J. Gordon. 

 (Simpkins.) Illustrated. 6s. 



Zoological Results based on Material from New Britain, Netv 

 Guinea, Jj-c. By Arthur Willey. D.sc, f.r.s. Part VI. (Cam- 

 bridge University Press.) Illustrated. 



A Popular Sistori/ of Astronomif during the Nineteenth Century. 

 By Agnes M. Clerke. 4th Edition. Revised and corrected. (A. & 



C. Blaok.) Illustrated, l.'is. 



The Foundations of Oeometry. By David Ililbert, PH.D. Trans- 

 lated by E. J. Townsend, ph.d. (Kegan Paul.) 4s. 6d. 



On the Distribution of Sain over the British Isles during the Year 

 1901. Compiled by H. Sowerby Wallis and Hugh Kobeit 

 Mill, D.sc, I.L.D. (Stanford.) lOs. 



Electrical Installations. By Kankin Kennedy, c.E. Vol. II. 

 (Caxton Publishing Co.) 



Induction Coils for Amateurs. Edited by Percival Marshall. 

 (Dawbarn & Ward. ) Illustrated. 6d. 



P. O. P. By A. Horsley Hinton. (HazeU.) Illustrated. Is. 



The Journal of the Anthropoloijical Institute of Qreat Britain and 

 Ireland. Vol. XXXII. Published by the Institute. 10s. 



Proceedings and Transactions of the Meteorological Society of 

 Mauritius. Vol, II. 



AsTKONOMiCAL. — Six Spectroscopic' binarie8,[in'addition 

 to the thirty-two previously announced, have lately been 

 discovered at the Lick Observatory, namely, <j) Persei, 

 rj Geminorum, y Can is Minoris, ? Herculis, o Equulei, and 

 e Andromeda?. Including three stars of this class detected 

 by Belopolsky, Prof. Campbell points out that out of 



350 stars observed, one in eight is a spectroscopic binary, 

 while many others are suspected, lie also expresses the 

 opinion that as the accuracy of measurement becomes 

 fjreatcr, the star which is not a spectroscopic binary will 

 ])rove to be the rare exception. The instruments for con- 

 tinuing the work in the southern hemisphere have been 

 completed, and it is lioped that the expedition may be 

 able to sail in the near future for Valparaiso, to occupy a 

 station near SantiriLTO, Chili. Mr. D. (), Mills has again 

 shown his appreciation of the work of the Lick Obser- 

 vatory by a gilt of a thousand dollars for improvements of 

 the Mills spectrograph, and Mrs- llearst has presented a 

 sum of 2')00 dollars to increase the equipment of the 

 Observatory. It is announced that copies of any of the 

 photographs taken at the Observatory may now be obtained 

 at moderate expense on application to the Director. 



The discussion of the connection between the variations 

 of terrestrial magnetism and solar activity lias chiefly been 

 confined to comparisons of magnetic phenomena with 

 sunspots, and it is well known that while the diurnal 

 range corresponds closely with the sunspot cycle, a difficulty 

 has arisen from the fact that a great sunspot may or may 

 not be accompanied by a magnetic storm. Sir Norman 

 Lockyer has recently investigated the magnetic variations 

 in relation to the observations of the chromosphere and 

 prominences made by the Italian observers during the last 

 thirty years, and has concluded that the epochs of great 

 magnetic storms correspond with those of the greatest 

 disturbances of the chromosphere near the sun's poles, 

 while the general magnetic curve agrees closely with that 

 of prominences observed near the solar equator. — A. F. 



BotanicaIj. — Torrejia for August contains, in a note by 

 Dr. M. A. Howe, some interesting information on the 

 vitality of the spores of Marsilia. Prof. D. H. Campbell 

 proved several years ago that the spores of M. wgi/pti'icii 

 may germinate when twelve years old. Some spores which 

 he obtained from dried specimens preserved for that peru)d 

 in the lierlin Botanical Museum germinated within thir- 

 teen hours after being placed in water. He found that 

 in the case of spores eleven years old fifty per cent, 

 germinated, and of those five years old nearly all grew. 

 According to Prof. Barnes, spores of Marsilin quadrifulia 

 retained their vitality after being kept for three years in 

 commercial alcohol. Dr. Howe has esperiuK'nted with 

 spores procured from material which had lain in the 

 herbarium for periods varying from twelve to thirty years. 

 The oldest spores which grew were practically eighteen 

 years old, and belonged to M. vestita. Nearly all the 

 megaspores formed prothalli with archegonia, and prac- 

 tically all the microspores reached an advanced stage of 

 germination, though only about half set free motile 

 spermatozoids. The first of these were seen in eleven 

 and a quarter hours after the sporocarps were placed in 

 water. — S. A. S. 



Entomological. — A Centipede of quite exceptional 

 interest has been described {Quart. Joiirii. Micr. Sci., 

 Vol. XLV., 1902, pp. 417-4.48) by Mr. K. I. Pocock. 

 It was discovered on the summit of Mount fiouincy, 

 Hobart, Tasmania, and it "proves to be comparable 

 in interest to either of its compatriots Ceratodus or 

 Ornithorrhynchus, as it unmi.stakably rcfiresents an 

 archaic type which has survived in this isolated corner 

 of the world." The species (Craterostigmtts tasiiHinifiigia 

 by name) possesses fifteen pairs of legs, like our 

 own well-known Lithobii, but it difBers from all other 

 known centipedes in having more tergites than sterniles 

 in its skeleton. There are fifteen of the latter, corre- 

 sponding with the pairs of legs, but twenty-one of the 



