May 9, 1889] 



NATURE 



35 



(2) The names of local Societies, or persons who are willing 

 to arrange for a photographic survey for geological purposes in 

 their district. 



The information afforded me will be placed before the Geo- 

 laical Section of the British Association at their next meeting, 

 and I trust to receive many offers of valuable assistance from 

 different parts of the country. If copies of photographs are 

 sent me they will be carefully kept for exhibition at the meet- 

 ing. Several geological friends have favoured me with sugges- 

 tions in regard to size of photograph, scales of height, length, 

 and other details, which will ail be carefully considered. Photo- 

 graphy is now so popular and easy of accomplishment that 

 there should be no difficulty in organizing local photographic 

 surveys for the purpose I have indicated. 



It was arranged at Bath that the delegates should get their 

 Societies to thinli the matter over, and that I should meanwhile 

 endeavour to prepare a list of local geological photographs 

 already available for study, 1 am communicating with the 

 Societies with this object, but your insertion of this letter will 

 further aid me in directing attention to the subject over a wider 

 circle than I am able to reach. Osmund W. Jeffs. 



12 Queen's Road, Reck Ferry, Cheshire, April 23. 



Columnar Structure in Ice. 



I HAVE just read Mr. James McConnel's interesting and im- 

 portant paper on the plasticity of ice (Nature, vol. xxxix. 

 p. 203), and as he remarks that it would be interesting to know 

 whether the columnar structure he describes as occurring in the 

 ice of the St. Moritz Lake has been observed in England, I 

 venture to ask you to record the fact that I recollect seeing a 

 precisely similar structure in the ice of the lake in Kew Gardens 

 in February 1880. The phenomenon occurred during a thaw 

 that preceded by a day or two the memorable snowstorm of that 

 month, and the aspect of the ice, where it had been broken 

 through, recalled to my mind that uf the well-known fossil 

 Lithostrotion basaltifor me, as it was budt up of vertical columns, 

 irregularly hexagonal in section, about a quarter of an inch in 

 diameter and of equal length with the thickness of the ice, 

 about 4 or 5 inches. If I remember aright, bright sunshine had 

 been thawing the ice during the day. I made a note on the 

 occurrence at the time, but as I came to India shortly after I do 

 not know what has become of it. 



T. D. La Touche, 

 Geological Survey of India. 



Camp near Cherrapunji, Assam, March 4. 



Brilliant Meteor. 



I SEND you an account of a meteor I saw on Saturday evening 

 last, thinking it may interest others as much as it has myself I 

 was lamp-signalling at the time (8. 55 p. m. ), and saw far the largest 

 meteor I have ever seen. It was far brighter than any planet, or 

 even than a good rocket. It seemed to start from the Great 

 Bear, and fall in a north-ea'-t direction half-way to the horizon. 

 I immediately stopped my message, and asked my companion 

 (a mile distant) if he had seen the meteor. He replied he had 

 not, which surprised me, though he had the town lights not far 

 behind him, and he was looking away from the north-east. I had 

 not finished asking him about the meteor, when I heard a loud 

 but distant report, which I can only put down to the same 

 source. It sounded like distant artillery, or more particularly 

 like a six-pounder at six miles distance on a still evening. The 

 interval of time between the sight and the sound I should 

 estimate at a minute. T. Herbert Clark, 



Wingfield, Trowbridge, April 30. 



A New Mountain of the Bell. 



Have the kindness to correct two typographical errors in my 

 communication describing the "New Mountain of the Bell," 

 printed in your issue of April 25. On p. 607, col. 2, line 7, 

 an unfortunate superfluous comma after the word quartz should 

 be expunged, so as to read quartz pebbles and veins. 



Near the bottom of the same column "modern gong" should 

 read "v/ooden gong." As a matter of fact the Nagous is far 

 from "modern." It consists of a heavy plank nearly 2 inches 



thick, 14 feet long, and sujpended by ropes at two points 4 feet 

 from either end. When struck with a wooden mallet, this 

 primitive gong emits a loud sound. At the Monastery of St. 

 Catherine, three of these are in use, one small one to call ta 

 their noonday meal the numerous cats which inhabit the 

 rambling old building. H, Carrington Bolton. 



London, May i. 



KLEIN'S ''IKOSAHEDRONr^ 



IT has recently been said, with great truth, that pure 

 mathematics is at the present moment the most 

 progressive of all the sciences. It is, we must confess 

 with sorrow, equally true, that the means at the disposal 

 of English pure mathematical students for making them- 

 selves familiar with the recent advances in their science 

 are deplorably scanty. This is not the place to discuss 

 the reasons why it has so long been the case in this 

 island that the stars of our mathematical firmament have 

 been 



' ' Etoilcs qui filent, filent et disparaient ! " 



and not fixed suns, with minor but still useful bodies 

 around them, receiving their light and completing their 

 systems. But it is obvious that this shortcoming has been 

 closely associated with the backward state of our text- 

 book literature in pure mathematics. There exist in the 

 English language so few books through whose pages the 

 reader can so much as descry the frontier land of pure 

 mathematics that every addition is an event of import- 

 ance. Such an addition is Mr. Morrice's translation of 

 Klein's " Ikosahedron." Klein's book is in many respects 

 the most charming piece of modern mathematical writing 

 that has appeared for many a day. It is a rare combi- 

 nation of great originality with wide and far-reaching 

 views, Teutonic minuteness of scholarship, and a candour 

 in dealing with the work of others which does not always 

 accompany the other high qualities just mentioned. If 

 we were asked to name a single book that would beyond 

 others give the reader a comprehensive glance over the 

 wide field of modern pure mathematics, and give him 

 an introduction to this study which would at once both 

 interest and instruct him, we should without hesitation 

 name Klein's " Ikosahedron." The work interweaves, in a 

 singularly felicitous and natural way, the most remote 

 and apparently unconnected branches of higher pure 

 mathematics. In the course of its perusal the reader 

 will make acquaintance with the geometry of the re- 

 gular solids, the theory of substitutions, the theory of 

 functions of a complex variable, invariants, the theory of 

 linear differential equations, Riemann's researches on the 

 hypergeometric series, Galois's theory of the resolution 

 of algebraic equations, elliptic functions, Pliicker's line 

 geometry, and the special theory of quintic equations. 

 This enumeration will sufficiently indicate the wide 

 sweep of the work ; but let not the reader be alarmed. 

 If he is ignorant of all these subjects, so much the more 

 will he enjoy the p]ea5ure of Prof. Klein's introduction 

 to them. He will find that he is led, by easy and 

 pleasant ways, first to see the interest and importance of 

 these subjects, then to panoramic aspects of them, and 

 finally to just so much detail as will make him (if he be 

 right-minded) thirst for more. Speaking from past 

 experience, we should say that one of the greatest dis- 

 advantages of modern specialism is the repulsive force 

 which it establishes at every point to the entrant. Let 

 an English student sit down, for example, to Jordan's 

 " Thdorie des Substitutions." He is at once plunged into a 

 sea of new terms and definitions. He is baffled by a 

 kaleidoscopic array of subtle distinctions between con- 



' " Lectures on the Ikosahedron, and the Solution of Equations of the 

 Fifth Degree." By Felix Klein. Translated by George Gavin Morrice, M. A., 

 M.B. (London ; Trubner and Co., 1888.) 



