December i6, 1897] 



NATURE 



157 



agreed that the report should be referred back to the Committee 

 for final consideration, and that as soon as complete it should be 

 issued to the Societies. The Hon. Secretary reported that a 

 National Photographic Record Association had been formed 

 under the presidency of Sir J. Benjamin Stone, M.P., who had 

 been at the head of the original Warwickshire Survey. He was 

 directed to communicate to the Association that " The Congress 

 hears with great satisfaction of the formation of a National Photo- 

 graphic Record Society, and expresses its desire to assist the 

 work in any way it can." 



Mr. W. a. Knight, writing from Bruton, Somerset, in- 

 forms us that on November 30, at 10.20 p.m., he was fortunate 

 enough to observe there a splendid lunar rainbow. The moon 

 was sufficiently near the horizon to give a large arc, and although 

 it was scarcely quarter-full, the black clouds looming in the 

 north-east made the bow appear quite bright. There appears to 

 be no doubt that what Mr. Knight saw was a lunar rainbow and 

 not a halo, for it was opposite the moon. 



Prof. A. Riggenbach has sent us the results of seven 

 years' rainfall observations at Basle, deduced from a self- 

 recording gauge. Of course the period is very short, and in 

 dealing with monthly and annual means the author combines 

 the values with those of an ordinary gauge, giving altogether a 

 series of thirty-three years. But the principal object of the 

 paper is to bring out some interesting details, which cannot 

 well be obtained from an ordinary gauge. Among these we 

 may mention the frequency and duration of very heavy showers, 

 the great majority of which last only about twenty minutes. 

 Sixty per cent, of these occur between ih. and 7h. p.m., and 

 87 per cent, occur between June and September. In the yearly 

 range the rainfall probability reaches a maximum in the early 

 summer and in the late autumn, while the minima fall in mid- 

 summer and in the first months of the year. In the daily range 

 the duration of rainfall reaches a maximum between 6h. and 

 8h. a.m., and falls to a shallow minimum at 7h. to 8h. p.m., 

 after which it rises uniformly to the maximum again. The 

 various phases are shown both in tabular and graphical form. 

 Dr. Riggenbach is perhaps best known to English meteorologists 

 by the success with which he has prosecuted cloud photography. 



Herr Otto Baschin contributes to the Verhandhmgen der 

 • Geselhchaft fiir Erdkunde zii Berlin an account of the fitting 

 out and departure of Andree's balloon expedition. The different 

 possibilities as to the fate of the explorers are discussed, and the 

 conclusion reached that there is as yet no reason to give up 

 hope of their return. Under the most favourable circumstances 

 the balloon might easily deposit its passengers on a part of 

 Northern Siberia, from which it would take months to reach 

 the nearest telegraph station. 



The new number of the Mittheiliuigen von Forschungs- 

 reisenden iind Gelehrten aiis den deutschen Schutzgebieten con- 

 tains some items. of geographical interest. Dr. F. Stuhlmann 

 contributes a paper on the German-Portuguese frontier in East 

 Africa, with a new map of the mouth of the Ravuma. In the 

 same region Lieut. Stadlbaur gives a short account of the Turu 

 district and its people ; whilst First Lieutenant Freiherr von 

 Stein describes the Ossa or Lungasi lake, on a tributary of the 

 Savaga in the Kameruns. 



Different minds place different estimates on the intellectual 

 accomplishments of the past half-century. In ordinary conver- 

 sation the men of the mart will point to an Eiffel tower, a 

 suspension bridge, a continental express train, a man-of-war, or 

 an Atlantic cable. But in a discourse recently delivered in 

 commemoration of the jubilee of the Sheffield Scientific School 

 of Yale University, President Oilman remarked that perhaps 

 the greatest triumphs of the intellect during the last half-century 



NO. 1468, VOL. 57] 



are these five contributions to human knowledge : the establish- 

 ment of the principles of evolution ; the establishment of the 

 principle of the conservation of energy ; the development of 

 mathematical science and its application to physics, mechanics, 

 electricity and astronomy ; the development of spectrum analysis 

 and the consequent discoveries respecting light and electricity ; 

 and the discovery of the nature and functions of bacteria, and of 

 their influence, for weal or woe, upon living organisms. 



As the result of an investigation of the red spectrum of 

 argon. Dr. J. R. Rydberg comes to the conclusion {Astro- 

 physical foumal, November) that it belongs to one single 

 element. Moreover, there seems to him to be no reason to 

 doubt that the blue spectrum belongs to the same element, but 

 corresponds to a higher temperature. As to the supposed dis- 

 placement of a great number of the lines of the white spectrum 

 towards the red end of the spectrum, it is remarked, " nothing 

 seems to indicate that we have to do with a continuous dis- 

 placement, but rather with the appearance of new lines on the 

 red side of those of the other spectra, with which they ought to 

 be closely related. In such a case it seems most probable that 

 the interesting observation of Eder and Valenta depends on a 

 change in the relative intensity of two sets of connected lines." 



In the Philosophical Magazine for December, Mr. J. D. 

 Hamilton Dickson examines the relation between the electric 

 resistance of a metallic wire and the temperature. Although 

 it has been demonstrated that platinum is a suitable substance 

 for determining temperatures over a very wide range, not much 

 different probably from 2000° C. , nevertheless, seeing that each 

 platinum thermometer needs at least to have its constant 

 specially and carefully determined, not by three, but by a series 

 of observations, it cannot be too strongly urged that this work 

 should in each case accompany the record of results when ex- 

 pressed in platinum temperatures ; and no one will deny that to 

 have these results expressed at once in terms of the normal air- 

 thermometer will permanently enhance the value of the work in 

 such a manner as to amply recompense the extra labour. With 

 the view of helping towards this desirable end, Mr. Dickson 

 proposes a formula of the form (R-i-a)'^ =/(/-(- (5), where a, /, b 

 are constants, and gives reasons for considering it as more repre- 

 sentative of the connection between temperature and resistance 

 than any formula hitherto proposed, and just as simple as any. 



An interesting extension to space of n dimensions of Euler's 

 and Meunier's theorems on the curvature of surfaces has been 

 given by Signor Luigi Berzolari in the Atti dei Lincei, vi, 

 10. The author proves the following propositions : — Given 

 in S« a form of « - i dimensions, the curvature (of Kronecker) 

 at any point of any hyperplane section is equal to the curvature 

 of the hyperplane section having the same trace on the tangent 

 hyperplane at that point divided by the n - 2th power of the 

 cosine of the angle between the hyperplanes. The curvature of 

 the normal hyperplane section at O is a maximum when the trace 

 of the cutting hyperplane on the tangent hyperplane at O is one 

 of the principal sections S» - 2 of the indicatrix, and the sum of 

 the curvatures of any « - i hyperplane normal sections mutually 

 at right angles is constant. 



Determinations of the thermal conductivity of ice by 

 different observers have hitherto exhibited a remarkable dis- 

 crepancy of results, the values of this coefficient being, accord- 

 ing to F. Neumann, o*34 ; De la Rive, o'i4 ; Forbes, 0*134 

 and 0*128, according to direction ; and, according to Mittchel, 

 0*30, the centimetre, gramme, minute and degree Centigrade 

 being taken as units. In the Atti dei Lincei, vi. 9, Signor Paolo 

 Straneo describes a simple method of determining this coefficient. 

 From observations on two different kinds of ice, taking two 

 different cubes of each, the values obtained are 0*307, 0*309 for 



