Sept. 14, 1876J 



NATURE 



423 



In the valleys which have, for example, a west-to-east 

 direction, and which were crossed by the ice moving from 

 north to south, the plastic ice ascended the slopes which 

 faced towards the north ; and also did it ascend on the 

 f jelds when it moved up a valley, a phenomenon which, 

 we know, is not at all uncommon. 



A second short paper, by Mr. Helland, gives a table of 

 the dimensions, heights above sea-level, and depths of 

 twenty Norwegian lakes, from which it is seen that these 

 lakes are, as in the case of the Italian lakes, deeply 

 excavated below the sea-level ; thus, for example, the 

 bottoms of the Horningsdalvand and of the Mjosen lie 

 respectively 432 and 331 metres below the level of 

 the sea. 



Without speaking of other short papers, we will note 

 that the " Year-Book" contains some practical information 

 on guides, on the regulations relative to hunting and fish- 

 ing, and finally, the Annual Report of the Committee of 

 the Society. It will be seen from this Report that the 

 Association is rapidly developing ; during 1875 the num- 

 ber of Fellows increased by 230, and reached, at the end 

 of the year, the number of 1,247, of whom i66 are foreign 

 Fellows, 63 belonging to England. A. L. 



OUR BOOK SHELF 



British Manufacturing Industries. Edited by G. Phillips 

 Bevan, F.G.S. Shipbuilding, by Capt. Bedford Pim, 

 R.N., M.P. ; Telegraphy, by Robert Sabine, C.E. ; 

 Agricultural Machinery, by Prof. Wrightson ; Railways 



« and Tramways, by D. Kinnear Clark, M.Inst. C.E. 

 (London : Stanford, 1876.) 



This ought to be one of the most popular volumes of this 

 instructive series, the contents are so varied, the subjects 

 so generally interesting, and the amount of information 

 conveyed so large. The various writers, moreover, have 

 managed to treat their subjects in a manner that will be 

 understood and enjoyed by even the most general readers. 

 Capt. Pim is evidently quite at home in his subject, which 

 he writes about in the spirit both of a sailor and a Mem- 

 ber of Parliament. Of course only the merest sketch of 

 so large a subject can be given in the space at his dis- 

 posal, but in that space he contrives to convey a sub- 

 stantial amount of information, commencing with the 

 log which conjecture makes the first form of boat, down to 

 the latest armour-plated ship-of-war. He writes in rather 

 a desponding tone of the present condition of British 

 shipping, both in the merchant service and in the navy, 

 and thinks our country behind others in modes of con- 

 struction. Our navy is evidently far from perfect, and 

 those who have its control, if they have also the welfare 

 of our country at heart, would do well to weigh Capt. 

 Pirn's criticism. One of the surest remedies is un- 

 doubtedly the rigid application of scientifically-conducted 

 experiment to shipbuilding. Mr. Sabine gives a very 

 complete sketch of telegraphy as an industry, of the 

 various forms of telegraph, their construction, the instru- 

 ments in use, and the materials employed. He, too, in- 

 dulges in some wholesome criticism, which those who 

 provide the means for constructing telegraphs would do 

 well to peruse. Prof. Wrightson (of Cirencester Agricul- 

 tural College) gives a very instructive account of the 

 multifarious machinery now used in the various opera- 

 tions by which agriculture is carried on, from clearing and 

 ploughing the land to preparing crops and stock for market 

 and consumption. Mr. Clark gives much valuable infor- 

 mation on the construction and working of railways, 

 showing the progress made since they were first started, 

 describing some of the latest improvements and most 



important enterprises, and entering into details as to cost, 

 revenue, and other points, which all who are interested in 

 railways will find useful. His short notice of Tramways 

 is also interesting ; their cost of construction will surprise 

 many, if not the large earnings which they make. 

 Altogether, the volume is one of varied and genuine 

 interest. 



LETTERS TO THE EDITOR 



\The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications. \ 



Miniature Physical Geology 



Under this title there is a brief but very interesting article in 

 Nature, vol. xiii. p. 310, describing, among other things, some 

 miniature earth-pillars at Bournemouth. These are due to the 

 slight protection afforded by a hard seam in the sandy rock to a 

 more friable layer beneath, when the whole is undergoing denu- 

 dation by rain. It is a thing which I have seen more than once j 

 but in the district of Luchon (Pyrenees) during the present 

 summer, I have come across instances of earth pillars in minia- 

 ture, yet more perfect than the above. The most striking case 

 was on a slope in the wood on the right bank of the Cascade 

 d'Enfer (Val de Lis). This slope consisted of a rather tenacious 

 clay, filled with small angular fragments of granitoid rock. A 

 slip, or the action of rain, had formed a Uttle corrie half a yard 

 or so wide, and on both sides of it the slope was studded with 

 earth pillars, more or less perfect, each capped by its httle stone. 

 These caps were rather tabular in shape, generally from a quarter 

 of an inch to an inch broad. Several of the pillars were so 

 exactly models of those at Botzen, that, if drawn on the same 

 scale, they could not be distinguished. The sides of the large 

 pillars are furrowed and fluted by little rills of rain ; so were 

 these. Boulders smaller than the great capstone are imbedded 

 in the matrix of the pillars, and, themselves exercising a protec- 

 tive influence are supported on brackets or pilasters of earth ; fo 

 was it here ; yet all this on the tiniest scale, for the largest and 

 best-formed pillar had r. general height of only about i| inches, 

 rising on one side about as much again above the bed of a minia- 

 ture ravine. I also saw a large number of similar but more 

 stumpy pillars by the side of the path from the Port de la Picade 

 to the Hospice de France. T. G. Bonney 



St. John's College, Cambridge 



Visual Phenomena 



The letter of Mr. Amulph Mallock (Nature, vol. xiv. p. 

 350) has very much interested me, having recently found that 

 my vision is an exception to that of other persons whom I have 

 tested in the matter. 



For instance, I see the light of distant street lamps clearly 

 defined without any diverging rays proceeding from the points of 

 light. 



Possibly this peculiarity of vision may partly account for my 

 having glimpsed the two outer satellites of Uranus with a refrac- 

 tor of only 4 "3 inches in aperture, during the last opposition of 

 the planet, and which caused some discussion when my obser- 

 vations were read before the Royal Astronomical Society. 



I have also been successful in detecting very faint stars close to 

 brighter ones with comparatively small telescopic aid. 



I may remark that I am long-sighted, as I can read the 

 columns of Nature readily between the distances of twelve to 

 thirty inches, though my more convenient reading distance is 

 about sixteen inches. 



It would be interesting to ascertain whether there are many 

 such exceptions to the " visual phenomena " pointed out by Mr. 

 Mallock. I. W. Ward 



Belfast, Sept. 5 



Although there can be little doubt that the explanation 

 of the long streaks of light seen on examining a bright point 

 through a half-closed eye, which is given in Nature, voL xiv. 

 p. 350, is the right one, and may be proved to be so in other 

 ways than those noted, yet I think the Fig. 5, which is sup- 

 posed to represent the course of the rays of light, ought not to 



