March 22, 1900J 



NATURE 



507 



Mathematical Society, March 8.— Prof. F:iliott, F.R.S., 

 Vice-President, in the chair. — The chairman announced that in 

 accordance with a resolution passed at the Council meeting, the 

 meetings of the Society would in future b2 held at 5.30 p.m. 

 instead of at 8 p.m. as heretofore. The days of meeting will 

 remain unaltered. — Prof. Elliott then dwelt upon the losses to 

 mathematics which had resulted from the recent decease of Prof. 

 E. Beltrami (Hon. Foreign Member), and of Mr. J. J. Walker, 

 F.R.S. The latter gentleman was almost an original member 

 of the Society, had served on the Council some twenty years, had 

 been a most regular attendant at its meetings, and had con- 

 tributed about twenty papers to its Proceedings. He had 

 served as Vice-President four years, and President two years. 

 Votes of condolence were unanimously passed in silence, and 

 the senior secretary was directed to communicate to the 

 relatives of the deceased the sympathy of the Society. — Prof. 

 Lamb, F.R.S. , read a paper, " Problems relating to the impact 

 of waves on a spherical obstacle in an elastic medium." — Mr. 

 W. F. Sheppard (Prof. Lamb, Vice-President, in the chair), 

 spoke on the use of auxiliary curves in statistics, with tables for 

 the curve of error. — Major Macmahon, F.R.S., Prof. Lamb 

 and Mr. R. Hargreaves, discussed points which arose out of the 

 communication. — A supplementary note on the theory ofauto- 

 morphic functions, by Prof. A. C. Dixon, was taken as read, 



Cambridge. 

 Philosophical Society, March 5. — Mr. J. Larmor, Presi- 

 dent, in the chair. — Considerations regarding the Zeemann 

 effect, by J. Larmor. — On the simplest algebraic minimal 

 curves and the derived real minimal surfaces, by H. W. 

 Richmond. The discovery of real algebraic minimal surfaces 

 of the lowest degrees forms a part of the first of the two 

 classical memoirs on the subject of minimal surfaces contri- 

 buted by Sophus Lie to Math. Annalen xiv. and xv. When 

 Lie's work is examined in the light of the fuller know- 

 ledge we now po.ssess concerning space-curves of orders three 

 or four, it appears that it is possible in most cases to write down 

 the equations of the curves and surfaces found by him in a 

 fairly simple form ; but that one of the surfaces that he quotes 

 is non-existent. — On Diophantine inequalities, by G. B. 

 Mathews. This is a continuation of a recent paper of Major 

 Macmahon's (Canib. Trans, vol. xviii). — Experiments on 

 impact, by J. H. Vincent. When inflated india-rubber balls 

 are allowed to fall on a stone floor the coefficient of restitution, 

 e, is found to be a linear function of the velocity just before 

 impact. This law holds also for a steel ball impinging on a 

 block of india-rubber ; but it does not hold for a steel ball im- 

 pinging on the plane surfaces of blocks of paraffin wax, lead, 

 brass and cast-iron. In these cases the curve obtained by 

 plotting e against 7' the velocity of approach is convex towards 

 the origin of co-ordinates and all the four curves are very 

 similar ; the value of e rises rapidly as v decreases. The per- 

 manent deformation produced by the impact was studied in 

 these cases and was found to obey remarkably simple laws. — 

 On the distance between the strice and on other phenomena 

 connected with the discharge of electricity, by R. S. Willows.— 

 The teaching of mechanics by experiment, by Prof. Ewing. 

 Prof. Ewing pointed out how by a course of suitable experi- 

 ments students could not only be rendered familiar with the 

 general principles of mechanics but could at the same time 

 learn how to apply these principles to practical questions, and 

 how to detect and allow for the causes which produce aberra- 

 tions from what may be called the theoretical result. He 

 exhibited in illustration of his remarks a number of self- 

 contained pieces of apparatus for experiments in statics, 

 dynamics and elasticity. 



Manchester. 

 Literary and Philosophical Society, March 6.— Prof. 

 Horace Lamb, F.R.S., President, in the chair.— Dr. F. H. 

 Bowman brought to the notice of the members the results of a 

 series of experiments recently made in regard to the preservation 

 of milk or cream by aeration. He explained that sterilised air 

 is aspirated through the milk or cream in suitable vessels ; and, 

 after aeration for about twenty minutes in the sterilised air at 

 ordinary temperature, it is found that the milk or cream so 

 treated will keep sweet for from eight to ten days, though ab- 

 solutely unchanged in composition in any way ; the same milk 

 or cream unaerated will become sour in two or three days. 



NO. 1586, VOL. 61] 



This discovery renders it possible f(?r milk or cream to be kept 

 or distributed in a perfectly pure and natural condition without 

 the use of any preservatives or antiseptics. — On the production 

 of nitric acid from air by means of the electric flame, by A. 

 McDougall and F. Howies. The experiments were carried out 

 with the view of obtaining the best conditions under which the 

 oxidation of the nitrogen took place. The effect of varying the 

 current in the flame was fully entered into, and the results 

 clearly showed that for a maximum oxidation to take place the 

 temperature of the flame must be as low as is consistent with 

 steady working. The mode of obtaining the electric flames in 

 parallel was described, and particulars were given relating to 

 the drop in volts observed at the electrodes when the discharge 

 is running. Various pieces of the apparatus used in the experi- 

 ments were exhibited, photographs of the larger parts being 

 thrown upon the lantern screen. 



Edinburgh. 



Mathematical Society, March 9. — Mr. R. F. Muirhead, 



President, in the chair. —The following papers were read : — 



A note on change of co-ordinate axes, by Prof. Steggall. — The 



conditions for multiple roots of the equation in A. (a— A, 



l>—\, )=o, by Chas. Tweedie. — The analytical 



representation of a potential function by means of cylindrical 

 and spherical harmonics, with applications to Green's problem, 

 by John Dougall. 



Dublin. 



Royal Irish Academy, February 26.— Mr. John Ribton 

 Garstin, F.S.A., Vice-President, in the chair.— Prof. D. }. 

 Cunningham, F.R.S., read, for Prof W. H. Thompson, a paper 

 by the latter on degenerations resulting from cortical lesions of 

 the temporal lobe. 



Paris. 



Academy of Sciences, March 12. — M. Maurice Levy in 

 the chair. — Notice on the works of M. Eugene Beltrami. — On 

 the sexual apparatus and double fertilisation in tulips, by M. L. 

 Guignard. The author has extended his researches on the 

 double fertilisation in the genus Lilium. Similar phenomena 

 were observed to take place in Lilium candidum to those 

 previously studied in L. Martagon and L. pyrenaicum, although 

 the work was more difficult in the case of the cultivated species. 

 In Endymion, however, there are differences in the female 

 sexual apparatus, since the two polar nuclei, the union of which 

 produces the secondary nucleus of the embryonic sac, approach 

 and touch each other long before the penetration of the pollen 

 tube into the ovule. But although flattened at the surface of 

 contact, they do not fuse, their contours remaining quite dis- 

 tinct. — On survey work carried out by Russian engineers by 

 the photographic method, by M. Laussedat. An account of 

 the survey operations for the Transcaucasian railway. The 

 photographic method is very expeditious, and costs only 

 about one-third of the usual survey. — On a new reaction 

 between certain aromatic aldehydes and the sodium de- 

 rivative of borneol, by M. A. Haller. The sodium 

 derivatives of three borneols, ordinary dextrorotatory and \x.\o- 

 rotatory borneol and loevorotatory isoborneol treated with 

 benzaldehyde in petroleum solution all gave the same benzyli- 

 dene-camphor. Derivatives are also described in which 

 methylsalicylic aldehyde and the corresponding para-compound 

 are substituted for the benzaldehyde. — On an application of 

 the method of successive approximations, by M. A. Davidoglou. 

 — On the integration of linear equations when the discriminant 

 is not zero, by M. J. Le Roux. — On the extension of the 

 properties of a reduced function to the fractions of interpolation 

 of Cauchy, by M. H. Pade. — The determination of standard 

 points in the spectrum, by M. Maurice Hamy. The author 

 combats the view put forward recently by MM. Perot and Fabry, 

 that the ray A508 of cadmium may vary slightly in wave-length 

 with the form of vacuum tube employed. The cadmium tube with- 

 out electrodes has shown no sign of variation in the constitution of 

 the rays emitted by it even after working for fifty hours.— Theory 

 of propulsive helices, by M. Rateau.— On gas motors, by M. L. 

 Marchis. An analysis and criticism of the usual treatment of 

 the cycle in gas engines. The usual assumptions lead to the 

 absurd conclusion that the explosion produces no increase of the 

 pressure.— On the experimental study of the Hertz exciter, by 

 M. R. Swyngedauw. According to the theory of Poincare and 

 Bjerknes, the Hertz exciter emits a deadened vibration, for 



