NATURE 



[January 5, 1899 



While the present monograph follows, almost inevitably, 

 the lines of Eichhoff s work, to which it constantly refers, 

 it is, so far as its extent goes, a great advance on that 

 book ; for the author has spared no pains in achieving an 

 exhaustive treatment of the subject, both by his own 

 observations and by collation of what has been written 

 by others. 



Mr. Lovcndal is artist as well as author, and is already 

 well known as the illustrator of Schiodte's " De Meta- 

 morphosi Eleutheratorum." He has executed for the 

 present work five plates, by the now almost disused 

 method of line-engraving, which cannot be surpassed for 

 beauty of style or accuracy of detail. The text is 

 furnished with some eighty woodcuts, showing the burrows 

 of these insects in bark and wood, and the whole book is 

 printed in the most sumptuous manner. 



Such a book, written entirely in Danish and on about 

 fifty species of a single Coleopterous family, is for the 

 very few. But it is worthy of more general examination 

 as a monograph which in method, fulness and finish, 

 leaves nothmg to be desired. The publication of a work 

 of this calibre would be, we fear, at present entirely beyond 

 the resources of British entomology. W. K. H. B. 



Through Arctic Lapland. By CutclifTe Hyne. Pp. 



xi + 284. (London : Adam and Charles Black, 189S.) 

 We have in this volume a very interesting account of 

 the authors journey from \'ardo Island, lying in the 

 north-east corner of Norway, to Haparanda, in Sweden, 

 situated at the head of the Gulf of Bothnia. Mr. Cutcliffe 

 Hyne was accompanied by his friend Mr. Cecil Hayter, 

 to whom he is indebted for the illustrations, which form 

 an attractive feature of the book. 



On arriving at Vardo, inquiries were made as to the 

 best means of getting across the country, and it was 

 found that the journey was an unheard-of undertaking in 

 the summer months, the country being chiefly swamps, 

 lakes and rivers. In winter it would have been com- 

 paratively easy, for the ground being hard, and the water 

 frozen, there were recognised routes, and stations where 

 relays of deer could be obtained. 



However, the travellers were not to be daunted by the 

 apparently hopeless look-out presented to them, and they 

 persevered, with the result that they accomplished what 

 they set out to do. 



The journey is of particular interest, for this special 

 route had never been taken before. The incidents 

 described are numerous and exciting, and the life and 

 customs of the nomad Lapp are well depicted. The 

 chief means of subsistence of this Lapp is in the possession 

 of large herds of deer ; for not only does their milk, which 

 is thick and syrupy, form part of his daily food, but he 

 breeds them, and rears them for selling and killing. With 

 regard to sledge-deer, it takes three years of severe train- 

 ing before they can safely be driven. 



All through the book we are struck with the descriptions 

 of the beauty of the vegetation, and also with the lack of 

 wild life. The troublesome swarms of mosquitoes and 

 flies form a special drawback for travelling in that part. 

 Nothing of great scientific importance is disclosed, but 

 much which will help those who wish to visit Arctic 

 Lapland. 



The New Gulliver. By Wendell Phillips Garrison. 

 Pp. 51. (Jaimica, Queen sborough. New York: The 

 .Marion Press, 1898.) 



This is an amusing fantasy in which a shipwrecked 

 graduate of Yale College is supposed to be cast upon an 

 island, and to hold dialogues with a dapple-grey horse, 

 which refused to acknowledge Prof. Marsh's Orohippus 

 or Eohippus as its ancestors, and explained that there 

 could be no moral sense without language : from which 

 conclusion certain theological distinctions .ire drawn. 

 NO. 1523. VOL. 59] 



LETTERS -JO J HE ED 11 OR. 



'jThe Elitor docs not hold himself reff>onsihle for opitiims < 1 

 pressel hy his correspomienls. Neither (an he tinitnake 

 to return, or to correspond with the writers of. rejected 

 manuscripts intended for this or any other part oj Nai URE. 

 A'o notice is taken of anonymous communications.] 



Converse of the Zeeman Effect. 



I HAVE not seen it noticed that a converse actifn to the 

 Zeeman eft'ect shoulil exist. A radiating atom in a magnetic 

 field gives out circularly polarised light. A circularly polarised 

 beam of light should cause a directed rotation of the electrons, 

 so that the absorbing gas should be magnetised and exhibit 

 magnetic force. If all the molecules in a c.c. of gas were 

 caused to rotate their electrons in the same direction, it would 

 possess quite a considerable magnetic moiiient. It is very im- 

 probable that the action of a circularly polarised beam of light 

 would control the motions to such an extent as that : but it is 

 quite possible that, if a circularly polarised beam of sunlight 

 were passed through a strongly absorbing gas, it would mag- 

 netise it to an observable extent. The same effect would 

 jirobably exist in any medium in which absorption was princi- 

 pally due to synlony and not mostly due to viscous actions. 

 Hence I would expect some effect 'vilh absorbing substances 

 like fuchsine. It is doubtful whether lampblack, iron, or other 

 metals have a sufficiently syntonous absorption to exhibit the 

 effect. 



My assistant Mr. Thrift is engaged in trying the experi- 

 ment, but in the meanwhile I thought it might be of general 

 interest to point out that such an effect should exist. 



Geo. Fras. KnzdERAi.n. 



Trinity College, Dublin, December 29, 1898. 



Flow of Water. 



I TOOK occasion, in the course of a paper on " The Character 

 of Fluid Motion," read on December 14 before the Liverpool 

 Engineering Society, to give the following reply, which I 

 promised to Prof Osborne Reynolds's letter, which appeared in 

 your issue of September 15 last. 



" Prof. Reynolds's comments may be placed under three 

 headings : 



"(l) .\n expression of disagreement with what he takes to be 

 my views on the .subject of the light border. 



" (2) .\n explanation of the light border or bands adjacent to 

 the solid boundary. 



" (3) The expre.ssion of the belief that the water charged with 

 air bubbles does not in any way represent the motion of the fluid 

 itself. 



" In the first place the criticism of Prof Reynolds is based, 

 apparently, upon a misconception of the statement in my first 

 paper ( 7';<;;/.t. Inst. Naval .■Architects, vol. xxxix. p. 151;. 



" In his letter he states as my views ' that with water in 

 sinuous motion and air bubbles as indices of the manner of 

 motion, the light bands adjacent 10 the surflices of the solids, 

 which show absence of bubbles adjacent to the solid, prove that 

 the once air-charged water has not been carried by sinuous 

 motion sufficiently near to the solid surface to displace the 

 initially .adjacent water ; and hence prove that the sinuous 

 motion does not extend up to the solid surface.' What I really 

 wrote was, however, very different to this, viz. that the result of 

 my observations had led me to the conclusion that the ' clear 

 border line represents a condition of (Mrallel flow of layers of 

 water past the skin of the obstacle, or the sides of a pipe, in 

 which a slate of shearing exists, while outside this, in the 

 darker portion, the w.iter is in a state of sinuous motion, which 

 corresponds to the state of the higher velocity of water.' 



" These two statements are really very different because it was 

 not my own belief that the once air-charged water never reached 

 the surface, but that when it did so, the air h.as been removed 

 from it for reasons which I gave {Trans. Inst, of Naval .\rchi. 

 lects, vol. xl. p. 45), where I staled that although I had 

 ' purposely avoided introducing unnecessary speculations in trying 

 to account for the observed facts, it does, however, seem that 

 the clear film may be j^Kirlly .accounted for as the result of inertia, 

 which allows the heavier water to reach the side of the .sub- 

 merged body, and partly from the fact that the velocity being 

 less there, the pressure might be greater, and .so the air being 

 excluded from the portion where the water is moving with 



