July 19, 1888] 



NA TURE 



269 



gives a fuller history and more minute details of the 

 results of the slip than were at that time accessible. It 

 mainly consists of an elaborate report, written by Dr. A. 

 Heim, the well-known Professor of Geology at Zurich, 

 " Ober-ingenieur " R. Moser, and Dr. A. Burkli-Ziegler, 

 to which are appended brief accounts of the incidents of 

 the catastrophe, and of that which occurred in 1435, and 

 lastly, a note on the disposal of the fund raised for the 

 benefit of the sufferers. Plans and sections (extracted 

 from the series which was attached to the above report) 

 accompany the book, and indicate very clearly not only 

 the amount of the mischief done, but also its cause, 

 which, as already stated in these pages, is the exist- 

 ence of a deep deposit of silt beneath the superficial 

 gravelly soil. The latter is but a very few feet thick, and 

 suffices for the foundation of the less important buildings ; 

 the former constitutes the shelving bed of the lake to a 

 depth of more than 100 feet. Borings made at various 

 stations on the land, not far from the lake margin, have 

 shown that this material remains incoherent to nearly the 

 above depth, after which it becomes stronger. Hence 

 there is always a danger of the underlying silt being 

 squeezed outwards into and upon the bed of the lake, and 

 the plans and sections furnished with the present volume 

 show precisely how the accident occurred. There appear 

 to have been some premonitory indications of the coming 

 mishap, in addition to the subsidence in the new pier 

 wall, which had already excited alarm. The inhabitants 

 of certain houses, which afterwards fell, had observed 

 sundry small displacements, which were especially shown 

 by the jamming of doors and windows ; cracking noises 

 also had once or twice been heard. But the actual 

 catastrophe was very sudden. About 3.20 p.m. the 

 end of the quay wall, which had been completed up to 

 a sort of little bastion, began to crack and sink. A 

 quarter of an hour later came the first great slip, which 

 caused the loss of seven ii-'es. Except for some minor 

 slips, there was then a pause for rather more than three 

 hours, and then at 6.50 p.m. the second and greater slip 

 occurred. A graphic account is given of the terror caused 

 by this second catastrophe, which caused the loss of four 

 more lives. A third, but comparatively unimportant, slip 

 occurred at 10.15 p.m. 



From the plan and sections it is evident that the second 

 slip affected the larger area, both of the land and of the 

 lake bed. Each slip forced the loose silt horizontally 

 outwards* so as to form a delta-like deposit on the lake 

 floor, thus diminishing the depth of the water sometimes 

 by about 4 or 5 yards. At the first slip a triangular 

 piece of ground, measuring about 80 yards a^long the shore, 

 and some 40 yards to its apex inland, was destroyed, and 

 the " delta " produced by this, which in outline resembles 

 a rather stout pear, is about 250 yards across the wider 

 part, and apparently extends to about 450 yards from the 

 shore. By the second slip not only a much larger piece 

 of the land (with a rudely oblong boundary) was removed, 

 but the lake bed opposite to it, for a distance of 220 yards, 

 appears to have slipped, so as to form a kind of broad 

 trench, resulting in an interval of deeper water some 

 50 yards wide. The material thus removed was deposited 

 over the deeper part of the lake bed, covering a space 

 not quite so wide as that occupied by the former " delta," 

 but much more than double the length, for its end is 



placed 1020 metres from the shore, at a depth of 

 44 metres. 



These elaborate maps and sections, with the results of 

 investigations (by means of borings) into the nature of the 

 lake bed, the level of the ground water, &c, give a high 

 value to this publication, which maybe commended tothe 

 notice of architects and engineers, as well as to those 

 interested in the history of Switzerland. 



OUR BOOK SHELF. 



Turbans and Tails ; or, Sketches in the Unromatic East. 

 By Alfred J. Bamford. (London : Sampson Low, 

 1888.) • 



The author of this book does not claim to have anything 

 very new or striking to tell his readers. He has seen a 

 good deal of India and China, and is content with repro- 

 ducing, in a popular way, the impressions made upon him 

 during his not very exciting sojourn in those countries. 

 He has little to say about " the mild Hindu " or "the man 

 of Han '' that tends to make us think more highly of 

 either. Mr. Bamford, like many English travellers, is apt 

 to be impressed by the bad rather than by the good 

 aspects of unfamiliar types of character ; and some of 

 his sweeping judgments would no doubt have been con- 

 siderably modified if, in estimating the intellectual and 

 moral qualities of Orientals, he had remembered more 

 frequently and vividly than he has actually done, that 

 thought and conduct in the East and West cannot always 

 be fairly or wisely measured by the same standards. The 

 book, however, has the merit of being written in a lively 

 style, and the author's judgments, whether sound or 

 unsound, invariably result from his own observation and 

 reflection. Here is one of a good many suggestive 

 anecdotes which brighten his pages : " Of what caste are 

 you ? " asked an Englishman of a native of India. " Oh," 

 replied the native, " I'm a Christian — I take brandy 

 shrab, and get drunk like you." 



The Photographer s Note-book. By Sir David Salomons, 

 Bart., M.A. (London: Marion and Co., 1888.) 



Both amateur and professional photographers, and 

 especially those who travel and take a great number 

 of photographs per day, will find this little book very 

 handy and useful, as it is of a very convenient size and 

 contains enough space for inserting the particulars, such 

 as number of stop, rapidity of shutter, remarks on the 

 light, &c, of each of fifty-one dozen plates. 



Formulae for enlargement and depth of focus and rules 

 for exposure are added, followed by a table, calculated 

 by Messrs. Marion, of the correct quantities to be taken 

 from 10 per cent, solutions to make up developers for all 

 the best known plates. The book concludes with various 

 tables, such as area enlarging, enlarging by linear di- 

 mensions, and equivalent focal lengths of lenses of 

 different sizes and makers. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he under- 

 take to return, or to correspond with the writers of, 

 rejected manuscripts intended for this or any other part 

 of Nature. No notice is taken of anonymous communi- 

 cations. ,] 



"Cloud Electric Potential." 



I DESIRE to draw ihe attention, mere particularly of your 

 electrical readers, to the following paragraph on p. 651 of the 

 eighth edition (1884) of Deschanel's "Natural Philosophy," 

 part hi., which appears distinctly at variance with the theory o 



