KNOWLEDGE & SCIENTIFIC NEWS. 



[Jan., 1905. 



REVIEWS OF BOOKS. 



The Mood. — "A Summan- of the Recent Advances in our Know- 

 ledge of our Satellite, with a complete photographic atlas," 

 by William H. Pickering, of Harvard College Observatory. 

 (John Murray. Price £z 2S.) 



It is the declared intention of the author of this 

 sumptuous volume to give an account of some of the 

 more recent advances in our knowledge of the moon, and 

 to leave to the text-books a statement of that earlier 

 acquired information with which most people are already 

 familiar. This statement of Professor Pickering's intention is 

 not quite fair to his accomplishment ; because it might lead the 

 reader to suppose that the book contained only such material 

 as had been already presented in the author's contributions 

 to the Har\-ard Observatory Annals, whereas the book might 

 best be defined as a brilliantly interesting essay on the 

 moon, coloured or supplemented by Professor Pickering's 

 views of the inferences to be drawn from the latest informa- 

 tion concerning it. Thus the first three chapters, written in a 

 vein which will appeal to any intelligent and educated person, 

 comprise the commonly accepted views as to the origin of the 

 moon, the data in regard to its distance, rotation, libration, 

 &c. ; and the opinions formed within the last few years by 

 many astronomers on the probable density and temperature 

 of a lunar atmosphere. Some of the new views arc hypotheses ; 

 some are of a nature more solid than that and are based on 

 the Harvard " discoveries " which the splendid Arequipa 

 station have enabled astronomers to add to the common 

 capital of astronomic science. In another particular new 

 •' views " of the moon are presented, for the volume contains a 

 complete photographic atlas of the moon, the plates of which 

 cover the whole visible surface of the moon five times. Eulogy 

 of these beautiful plates is superfluous ; they h.ave been made, 

 and they have been selected and printed, with one object alone 

 in view, which is that the Harvard College Observatory, and 

 the expedition which it sent out to Jamaica in 1899 for the 

 special purpose, should have the honour of presenting the most 

 complete and the most scientifically useful set of photographs 

 of the moon in existence. With, or (as Professor Pickering's 

 opponents might say) without, some of the deductions which 

 are drawn from his examination of the moon's surface, they 

 mark a fine achievement, and are an enviable possession. 

 There are nearly a hundred plates in all ; and they con- 

 stitute the only complete lunar atlas in existence. The 

 first point on which Professor Pickering may be said to 

 invite controversy is in respect of the moon's atmosphere, 

 water and temperature. He gives observational grounds 

 for believing that an atmosphere exists at the moon's surface, 

 comparable in density to that which would be found at a 

 height of about 30 to 40 miles above the surface of the earth. 

 A haze, he adds, appears to rise to a height of about three or 

 four miles on the sunlit side of the moon. Accepting Professor 

 Pickering's observations as accurate, what is to be said of his 

 explanation that water and carbonic acid gas are escaping from 

 the moon at such a rate as to constitute an atmosphere of the 

 kind he predicates, or to give rise to permanent snow fields ? 

 The opposed view is that the gases in question would escape 

 too quickly from the moon's surface — the force of gravity there 

 being insufficient to retain them — and that some other expla- 

 nation must be found. Professor Pickering's hypothesis, while 

 explaining with apparent satisfaction that the observed enlarge- 

 ment of the white spots of Linnc towards lunar sunset and 

 during a lunar eclipse are due to a sublimation of hoar frost, is 

 peculiarly difficult of application to the systems of bright streaks 

 which radiate from some of the lunar craters, and which are 

 attributed to snow produced by allied causes. Similarly 

 Professor Pickering, from the consideration of the darkening 

 of certain areas of the moon's surface and their increase of 

 size during the lunar morning, together with their dis.appear- 

 ance towards the time of sunset, arrives at the conclusion 

 that a luxuriant vegetation springs up on the moon, nourished 

 by water which it derives by capillary forc<; from the soil and 

 fostered by the sun's heat to a giant growth that is aided by 

 the small gravitational attraction of the moon itself. Against 

 this hypothesis, fascinating but fanciful, we have to set the fact 

 that no terrestrial life exist ■; on terrestrial mountains 20,000 feet 

 or more above the sea under atmospheric and thermometric 



conditions which must be vastly more favourable than 

 those to be found on the moon. Furthermore, as another 

 writer has said, whatever may have been the circum- 

 stances which led to the beginning of life on this earth, 

 they were evidently of rare occurrence. The fate of 

 the moon as a habitation for any form of life, as we 

 know it, was probably in large part determined by the ratio 

 between its gravitative force and the energy of the kinetic 

 movement of the gases which constituted its atmosphere. If 

 that energy had been suflicient to keep them on the satellite, 

 there is no reason why it should not have had the history of a 

 miniature earth. These postulates are palpably non-admissible, 

 and it is most reasonable to suppose that the moon has not 

 even vegetable life as we know it. These are, however, only 

 " spots on the moon," and we should not be justified in reg.ard- 

 ing them as such, were they presented with any less appear- 

 ance of incontrovertible and established truth, in a volume 

 which is not a controversial work at all, but is clearly intended 

 to inform the growing class of people who, without being 

 experts, are deeply interested in science. If, however, they 

 bear in mind that — to adopt an .Vmerican expression — all Pro- 

 fessor Pickering says does not " go," then in buying and read- 

 ing this fine work they will be richer by the knowledge of in- 

 genious, interesting, and fascinating theories, as well as by a 

 solid possession of great instructional value. 



Game, Shore, and Water Birds of India, with additional refer- 

 ences to their allied species in other parts of the world, by 

 Colonel A. E. Le Messurier, C.I.E., F.Z.S., F.G.S., fourth 

 edition (London : Thacker and Co., 1904). Works on the 

 birds of India are not numerous, and sportsmen, as a rule, have 

 found them either too bulky or too technical. That is to say, 

 these works have been designed rather for the ornithological 

 student than the campaigner. Though the standard, in short, 

 of these tomes has been an unusually high one, they are not 

 adapted to the use of men who must travel with as little 

 luggage as may be. Colonel Le Messurier was one of the 

 first to realise this, and so far back as 1874 he prepared a 

 volume, for private circulation only, on the " Game Birds of 

 the Eastern Narra." I-"our years later — in 187S — this book 

 was issued to the public with some slight additions. This year 

 was made memorable in the annals of Indian Ornithology by 

 the appearance of the first volume of Hume and Marshall's 

 •' Game Birds of Indii," a work which quickly made its in- 

 fluence felt. Colonel Le Messurier was among the first to 

 realise the sterling value of these volumes, and we find, indeed, 

 that in his next edition he begs to acknowledge that the addi- 

 tions therein made are largely taken from this source. That 

 the author's efforts to produce a handy and portable guide for 

 the use of sportsmen were fully appreciated may be gathered 

 from the fact that a fourth edition has been called for. It is 

 highly probable that this last will meet with as cordial 

 a welcome as the earlier volumes ; inasmuch as all the 

 features which secured success for the earlier editions 

 are preserved here, and considerable additions have been 

 made. Viewed, however, from an entirely impartial stand- 

 point, it must be admitted that a great opportunity has 

 been missed in this new voltnne. There can be no doubt but 

 that the introduction reqtiiresdrastic alterations. As it stands 

 it is useless alike to the scientific student and to the sports- 

 man, and errors are painfully common. The classification 

 adopted is antiquated. The quotation from Professor Kitchen 

 Parker — unacknowledged, though placed within inverted 

 commas — was more or less true when he wrote it in 1875. But 

 in 30 years much has been done in this matter. On the ques- 

 tion of migration, the author relics almost entirely on Professor 

 Newton's masterly article in the ninth edition of the " Itncyclo- 

 pccdia Britannica." But, as touching the mysterious irrup- 

 tions of Pallas's sand-grouse into Great Britain, we would 

 gather that the last of these occurrences took place in 1872! 

 Other equally important matters are treated in the same 

 perfunctory m.anner. Under a double heading, of ponderous 

 capitals, the question of" Extern.al Variation in the Two Sexes 

 and at Different S(;asons" isdiscusscd, and dismissed, in (hree 

 paragraphs of two lines e.ich ! The subject of nidification is 

 dealt with in 16 lines ! L'nder the curious plea that, "owing 

 to the facilities of travel, Anglo-Indians are now engaged in 

 most countries either in business or pleasure," the author, in 

 this edition, includes references to "all species in other parts 

 of the world that are allied to the game, shore, and water 

 birds of India." Surely even Anglo-Indians cannot contrive 



