94 



NATURE 



[November 27, 1902 



of the same concentration. The object of the present paper is to 

 find an explanation of this anomalous behaviour of sulphuric acid, 

 and of the effect produced by the addition of chloride. It has 

 long been known that, when an aluminium electrode is employed 

 as anode in a solution of a sulphate or sulphuric acid, there is a 

 very great resistance offered to the current, and that this resist- 

 ance is due to a film which separates the electrode from the 

 solution. If the aluminium is the kathode, or if other acids are 

 substituted for sulphuric acid, this great resistance does not 

 exist. It seems probable that the two phenomena are related, 

 and that the film is also the cause of the slow action of sulphuric 

 acid on aluminium. The authors have attempted to establish 

 a theory which will explain these phenomena. The influence of 

 certain salts of potassium in various concentrations was investi- 

 gated, and the authors conclude that the presence of certain ions 

 enables a large current to pass through the cell. The reason 

 seems to be that the film of aluminium hydroxide with which 

 the anode is covered is permeable to certain ions but imperme- 

 able to others. The anomalous behaviour in sulphuric acid 

 would then be due to the impermeability of the film to the SG 4 " 

 ions and also to the Al" ions. Further experiments gave 

 support to the view that the abnormal behaviour of aluminium 

 anodes in sulphuric acid is due to impermeability. — A paper on 

 a determination of the ratio of the specific heats at constant 

 pressure and at constant volume for air and steam was read by 

 Mr. Mackower. The method employed in this paper is similar 

 to that used by Lummer and Pringsheim, and consists in allow- 

 ing the gas under investigation to expand adiabatically and 

 measuring the lowering of temperature caused by such expansion. 

 The author's value for the ratio of the two specific heats in the 

 case of air is I '401. The observations with steam were similar 

 to those in the preceding experiments, but special precautions 

 were necessary to prevent the condensation of the steam in the 

 tubes leading to the vessel. The results for steam were not 

 sufficiently accurate to justify the application of corrections 

 for radiation and for conduction and convection. The values 

 of 7 deduced from two series of experiments were I '307 and 

 I -304. 



Royal Astronomical Society, November 14. — Dr. 

 J. W. L. Glaisher, F. R.S. , president, in the chair. — 

 Dr. Isaac Roberts read a paper on Sir W. Ilerschel's nebulous 

 regions, compared with photographs of the same regions taken 

 simultaneously with the 20in. reflector and 5m. Cooke lens. 

 The results show that on forty-eight of the areas described by 

 Herschel as nebulous there is no visible trace of diffused 

 nebulosity, while on the remaining four there is nebulosity with 

 very characteristic features. Photographs of these remarkable 

 nebulous regions were thrown on the screen. — Prof. H. H. 

 Turner read a paper on the suggestion made by Sir D. Gill that 

 the brighter stars are, as a whole, rotating with respect to the 

 fainter stars as a whole. A comparison of photographs taken 

 at Oxford between 1892 and 1902 indicated a relative motion 

 of the brighter stars of about the same amount as that found by 

 Sir D. Gill, but in the opposite direction. Prof. Turner made 

 the suggestion that the stars nearest to the sun may be, generally 

 speaking, intrinsically fainter than those of the Milky Way, 

 and there would thus for some regions be a discontinuity in the 

 law by which fainter stars are, as a whole, more distant than 

 brighter stars. — The secretary read a paper on the same subject 

 communicated by the Astronomer Royal. A comparison has 

 been made between Groombridge's catalogue (1810) and the 

 Greenwich second ten-year catalogue (1S90). The results, so 

 far obtained, could not be taken as affording evidence of the 

 cosmical movement suggested by Sir D. Gill. — Mr. E. T. 

 Whittaker read a paper on the general solution of Laplace's 

 equation and of the differential equation of wave- motions, and 

 on an undulatory explanation of gravitation. The principal 

 result was the general solution, by means of a definite integral, 

 of the well-known partial differential equation which is satisfied 

 by all Newtonian potential functions. It was then shown that 

 a definite integral of a similar type furnished the general 

 solution of the partial differential equation which occurs in 

 the theories of light, sound and electromagnetic waves. From 

 relations between the two solutions thus obtained, it was shown 

 that any disturbance which can be represented by a solution of 

 Laplace's equation can be compounded from simple uniform 

 undulatory disturbances, and it was suggested that this analysis 

 might furnish the explanation of the propagation of gravity. — 

 Photographs of Perrine's Comet, taken at Greenwich, &c, were 

 shown on the screen. On one of the Greenwich photographs, 



NO. 1726, VOL. 67] 



no less than seven tails were shown, one of them a degree in 

 length. — A paper by Dr. Max Wolf on stereoscopic pictures of 

 Perrine's Comet was read, and the photographs exhibited. — The 

 secretary read papers by Mr. Percival Lowell on an expedition 

 to determine the best situation for an observatory and on a 

 proposed standard scale of " seeing." — Mr. H. C. Plummer gave 

 a short account of his second paper on the images formed by a 

 parabolic mirror. — Other papers were taken as read. 



Geological Society, November 5. — Prof. Charles Lapworth, 

 F. R. S. , president, in the chair. — The secretary read a com- 

 munication, transmitted by the Rt. Hon. the Secretary of State 

 for the Colonies, from Mr. H. Powell, Curator, Botanic Station, 

 St. Vincent, to Dr. D. Morris, C. M.G. , Imperial Commissioner 

 of Agriculture for the West Indies, referring to the eruption of 

 the Soufriere on September 3 and 4. At 3 p.m. on September 3, 

 the corrected barometrical reading was 29*947, and the attached 

 thermometer Ss° F. Mr. Powell was informed that during the 

 day a lot of matter was ejected over the western lip of the old 

 crater down the Laricor or Roseau Valley to the sea. At 

 9.55 p.m., as seen at the Botanic Station, the eruption com- 

 menced in earnest ; flashes of fiame and lightning were visible 

 over the Soufriere at intervals of twenty to thirty seconds, with 

 frequent longer intervals. At 10.30 p.m., the corrected reading 

 of the mercurial barometer was 30'IOS and the attached 

 thermometer Sl = "5 F. From about this hour, the discharges and 

 accompanying noises increased in frequency and severity, and at 

 1.30 a.m. (September 4) the Soufriere was in full eruption. From 

 this hour to 2 a.m., the eruption was more severe than on May 7, 

 the explosions seeming to be louder and more continuous, and 

 the electric discharges, owing, doubtless, to its being night, im- 

 measurably grander and more awe-inspiring. At 2 a.m., the 

 corrected barometrical reading was 30 045 and the temperature 

 8l°F., and at 3 a.m. the corrected reading was 30*035. The 

 marvellous electric display was checked by a heavy shower from 

 the east, and the roar was correspondingly lessened. From 

 about 1.30 a.m., a cloud black as gunpowder was seen advancing 

 southward from the Soufriere, and at 2.30 this cloud had assumed 

 a circular form and was overhead of the Botanic Station. The 

 discharges from this cloud and to northward were exceedingly 

 numerous and severe, and the appearance generally was as 

 though myriads of long, fiery serpents were darting hither and 

 thither, and a constant crackling noise was heard, in addition to 

 the roar of the volcano. The chief disturbances seemed to be 

 west of the Soufriere, in the direction of Martinique ; and the 

 writer is strongly of opinion, from observations at the time, that 

 Mont Pelee and the Soufriere were in action together, but so far 

 no news has come from Martinique. At 3 a.m. (September 4), 

 the discharges and roar to the west nearly subsided, and the 

 Soufriere alone seemed in action, but more on the windward 

 side. From 3 to 4 a.m., the eruption gradually slackened, and 

 at the latter hour had nearly ceased. The next morning, the 

 barometer was normal at 29950. — A second communication 

 (also received through the Secretary of State for the Colonies) 

 was read, dated Grenada, September 23, from Sir R. B. 

 Llewelyn, Governor of the Windward Islands, expressing the 

 hope that some scientific observers might be induced to go out 

 to the West Indies and settle there for some time, in order to 

 accumulate information as to volcanic and kindred phenomena. 

 — The fossil flora of the Cumberland coalfield, and the palseo- 

 botanical evidence with regard to the age of the beds, by Mr. 

 E. A. Newell Arber. The succession of Upper Carboniferous 

 rocks in the region in question is apparently twofold — an 

 arenaceous series, 600 feet thick, consisting of massive sandstones 

 alternating with shales and fireclays, overlying argillaceous and 

 carbonaceous deposits, the latter forming the productive portion 

 of the coalfield and containing three great coal-seams, traceable 

 throughout the district. The Upper or Sandstone series has 

 yielded very few plant-remains from its upper division, but from 

 the lower division a long list of plants is given. A con- 

 sideration of the palceobotanical evidence has led to a reclassifi- 

 cation of the rocks. — Some remarks upon Mr. E. A. Newell 

 Arber's communication : on the Clarke collection of fossil plants 

 from New South Wales, by Dr. F. Kurtz. Agreement was ex- 

 pressed with Mr. Arber's identification of Rhiptozcunites Goep- 

 perti, which was taken to be a synonym of Notggerathiopsis 

 Hislopi. Podozamites elongatus, however, was regarded as dif- 

 ferent from Noeggeratliiopsis Hislopi. It was not considered 

 that there is sufficient evidence to warrant the separation of 

 Otopteris ovata from Rhaiopteris inaequilatera, in which species 

 it may be retained, perhaps as a variety. Rh. inacquilatcra 



