August 17, 1905] 



NA TURE 



387 



goddess of fertility, therefore of good luck and all genial 

 influences ; hence little gold and silver pigs were offered 

 to her, and also worn by Roman ladies, partly to ensure 

 pregnancy, and partly for luck." 



The recent issues of the Monthly Wcaihcr Review of 

 the U.S. Weather Bureau contain, inter alia, some im- 

 portant articles by Prof. Bigelow on the application of 

 mathematics to meteorology, on the diurnal periods in the 

 lower strata of the atmosphere, and on the observations 

 with kites at the Blue Hill Observatory, from 1897-1902. 

 In the first-named paper, the author points out that no 

 branch of modern science has suffered more severely than 

 meteorology by the misapplication of good mathematics to 

 good observational data, and that the results of recent 

 balloon and kite observations show that nearly the entire 

 range of general theory of the circulation of the atmo- 

 sphere must be pronounced a misfit. We think we are safe 

 in saying that no other meteorological journal can compare 

 with the Monthly Weallier Review in its endeavour to 

 popularise meteorological science, by the publication of 

 original articles, reprints, and translations from foreign 

 papers. The ordinary meteorological tables are based on 

 data from about 3583 stations, some of which belong to 

 countries outside the United States. Since December, 1904, 

 the Weather Bureau has received a large number of 

 reports giving simultaneous observations over the Atlantic 

 and Pacific Oceans made at Greenwich — noon. These are 

 charted, and, with corresponding land observations, will 

 form the framework for daily weather charts of the globe. 

 As a further instance of disseminating useful information, 

 we may refer to an article on forecasting the weather and 

 storms, by Prof. W. L. Moore, in the National Geo~ 

 graphic Magazine for June, illustrated by a number of 

 weather charts. The author points out, with justice, that 

 to anyone who will read the te.xt, and carefully follow 

 the charts which illustrate and make it clear, the daily 

 weather chart will be an object of interest as well as of 

 pleasure and profit. Every step taken, from the receipt of 

 the observations to the publication of the weather chart 

 and preparation of forecasts, is explained with clearness 

 and precision. 



Several simple forms of instruments affording a rapid 

 and accurate means of determining the paths of refracted 

 and reflected rays through any optical system are described 

 by Mr. J. R. Milne in the Proceetlings of the Royal Society 

 of Edinburgh (vol. xxv., p. 806). 



It is well known that the minimum potential of a point 

 discharge is increased by the discharge, a blunting or 

 powdering of the point occurring. That the blunting 

 is, however, not responsible for the rise in potential 

 appears evident from a series of experiments made bv 

 Mr. F. R. Gorton and described in the Verhandl- 

 ungen of the German Physical Society (vol. vii., p. 217), 

 where it is shown that under the influence of either an 

 ultra-violet radiation or the radiation of radium the blunted 

 point recovers its original value for the minimum potential. 

 The blunting of the point is thus a minor factor in the 

 question, and the conditions are investigated in which 

 constant, reproducible values can be obtained so that the 

 subject may be more fully investigated. 



In the July number of the American Journal of Science 

 Mr. D. Albert Kreider describes a special form of volta- 

 meter in which the accuracy and sharpness of the volu- 

 metric method of estimating iodine by means of sodium 

 thiosulphate are utilised. A special form of potassium 

 iodide cell is adopted in which iodine is liberated by the 

 NO. 1868, VOL. 72] 



action of the current ; its amount is then readily ascer- 

 tained by direct titration. The results obtained agree very 

 closely among themselves if a certain current be not ex- 

 ceeded, the difference then not exceding i part in 10,000; 

 but the results are uniformly higher by 006 per cent, to 

 009 per cent, than are shown by a silver voltameter placed 

 in the circuit. The rapidity and simplicity of the method 

 should adapt it for practical application. 



Prof. Balbiano, writing in the Atti dei Lincei, xiv., 12, 

 gives an account (read June 18) of the work of Prof. 

 Augusto Piccini, whose death occurred on April 16. While 

 Piccini's most important researches were connected with 

 the periodic law of Mendel^eff, attention is directed to a 

 little-known article on oxygenated water written by him 

 two years ago for the " Encyclopaedia of Chemistry," in 

 which the theory was advanced that the atoms of oxygen 

 which it contains are in the form of a combination inferior 

 to that of water. 



An interesting application of the mathematical theory 

 of elasticity is given by Prof. Vito Volterra in the Atti 

 dei Lincei, xiv., 12. The problem is that of an elastic 

 ring or hollow cylinder of rectangular radial section from 

 which a slice is removed and the separated parts joined 

 together, and the two cases are considered where the 

 fissure is radial and where the portion removed is of 

 uniform thickness. From calculation, the author found 

 expressions representing increase of internal length, de- 

 crease of external length, and distortion of the lateral 

 surface of the cylinder into a form concave outwards, and 

 experiments conducted with actual cylinders of caoutchouc 

 closely reproduced all the results of calculation. 



Dr. Roberto Bonola, of Pavia, discusses in the 

 Lombardy Rendiconii, xxxviii., 11, the theorems of Padre 

 Gerolamo Saccheri on the sum of the angles of a triangle, 

 in connection with Dehn's researches, Euclid's axiom of 

 parallels, and the postulate of Archimedes. Saccheri's in- 

 vestigations were published at Milan in 1793 under the 

 title " Euclides ab omni naevo vindicatus," and were 

 based on the consideration of " bi-rectangular isosceles 

 quadrilaterals," this term being used to designate a quadri- 

 lateral ABCD having AB = CD, and 



angle ABC = BCD = go°. 

 In ordinary space such a quadrilateral is a rectangle. 

 Padre Saccheri gives a proof that if one bi-rectangular 

 isosceles triangle has its remaining angles acute, right, 

 or obtuse, the same property will be true of every other 

 such quadrilateral. From this he deduces that if one 

 triangle has the sum of its angles greater to, equal to, 

 or less than two right angles, the same will be true of 

 every other triangle, i.e. the property commonly known 

 as Legendre's theorem on the angles of a triangle. Dr. 

 Bonola refers to Dehn's work in proving that Legendre's 

 theorem is independent of the postulate of Archimedes, 

 and he gives corresponding proofs in connection with 

 Saccheri's work. 



A SIXTH edition of Mr. A. B. Lee's " Microtomist's 

 Vade-mecum : a Handbook of the Methods of Microscopic 

 Anatomy," has been published by Messrs. J. and A. 

 Churchill. The first edition of the work appeared in 

 March, 1885, and was reviewed in our issue of June 18 

 of the same year (vol. .xxxii. p. 147). Many of the sug- 

 gestions made on that occasion have since been adopted. 

 The text of the book has been even more condensed than 

 in the last edition, and this plan has given room for much 

 new matter. The chapter on staining with coal-tar colours 



