190 



NATURE 



June 



i^q6 



ebonite, shellac, lampblack, water, and carbon bisulphide must 

 behave towards these rays in the same manner as they have been 

 found to behave towards Rontgen rtiys. — A new form of 

 mercurial air-pump, and the preservation of the vacuum in 

 Kiintgen tubes, by R. W. Wood. The author describes a 

 simple pump consisting of a system of tubes and bulbs contain- 

 ing the vacuum tube in one branch. It is completely closed, 

 and the vacuum is restored at will by simply oscillating the 

 whole apparatus. 



Bulk/ill de la Soa'i'tc' ties Natttralistes de Moscoii, 1895, No. 

 2. — Contributions to the knowledge of the molecular forces, as 

 a foundation to thermodynamics, by J. Weinberg; fourth part, 

 dealing with capillarity and adhesion. — The development of the 

 occipital region of the lower verterbrates, in connection with the 

 question of metamery of the head, by A. Sewertsoff. An 

 elaborate and suggestive work, in German, with two plates. — 

 On the rotation of the earth, supposed to be fluid in its interior, 

 by Th. Sloudsky, in French. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, June 4. — " Observations on Atmospheric 

 Electricity at the Kew Observatory." By Dr. C. Chree. 



The primary object of the investigation was to arrive at a 

 more exact interpretation of the records obtained with the Kew 

 electrograph, and to devise improvements in the conditions 

 under which it works. The electrograph curves are intended 

 to give the value of the potential at the point in the air where a 

 water jet issuing from a long pipe breaks into drops. The 

 proximity of a tall building has naturally, however, a large 

 influence on the potential, so that no direct estimate could be 

 made of the true potential gradient, i.e. the increase in potential 

 per unit of height in the open. 



Some preliminary experiments were made, which may be 

 regarded as verifying Prof. Exner's experimental conclusion that 

 a building under normal conditions reduces the potential in its 

 neighbourhood, as if it formed an integral part of the earth's 

 surface. Subsequently four series of observations were made. 

 The respective seasons were November-December, 1S94, 

 March-April, June-July, and October-November, 1895. The 

 observations were taken with a portable electrometer of known 

 scale value, at one or two approximately constant hours, at five 

 or six stations on or near the Observatory. 



The results were consistent with the view that such general 

 phenomena as diurnal or annual variation of potential got out 

 with the same instrument at the several stations would show a 

 good agreement. 



A comparison was also made between the potentials deduced 

 from the electrograph curves and the readings of the portable 

 electrometer. 



The values of the several meteorological elements, at the 

 times of the observations with the portable electrometer, were 

 derived from the Observatory records. 



They afforded the opportunity of carrying out a searching 

 investigation into possible connections of the several meteoro- 

 logical elements and the potential gradient. Attention was 

 particularly directed to data bearing on Exner's theory, which 

 connects potential gradient with density of aqueous vapour 

 through a definite formula, departures from which are to be 

 regarded as abnormal and due to disturbing causes. Special 

 -attention was also devoted to the possible influence of bright 

 sunshine in reducing the potential gradient, in consequence of 

 the theory proposed by Elster and Geitel. 



The results of the investigation seem far from favourable to 

 Exner's hypothesis. They afford a certain amount of general 

 support to Elster and Geitel's theory, inasmuch as on an average 

 potential seemed lower after long previous sunshine. The 

 evidence, however, in favour of a connection between high 

 potential and low temperature, high barometric pressure, low 

 wind velocity, and anti-cyclonic conditions generally, seems 

 about equally strong with that in favour of Elster and Geitel's 

 theory. In each case notable exceptions appeared to any general 

 xule. 



Chemical Society, May 28. — Mr. A. G. V. Ilarcourt. 

 President, in the chair. — Prof. P. P. Bedson delivered the 

 Lothar Meyer Memorial Lecture. The lecturer reviewed 

 Meyer's contributions to our knowledge of the gases contained 



NO. 1 39 I, VOL. 54] 



in the blood and of the periodic law, and gave an account of 

 the work done by the late German chemist towards promoting 

 the systematic arrangement of inorganic chemistry, pointing out 

 how great had been Meyer's influence on the promotion and 

 advancement of chemical theory during the past thirty years. 



June 4. — Mr. A. G. V. Harcourt, President, in the chair. — 

 It was announced that an adilress is to be presented to Prof. 

 Cannizzaro on the occasion of his seventieth birthday in July 

 next ; an address is also being presented to Lord Kelvin on the 

 completion of his fiftieth year as Professor of Natural Philosophy 

 in Glasgow University. The following papers were read : — On 

 magnetic rotatory power, especially of aromatic compounds, by 

 W. H. Perkin. The author describes apparatus used for deter- 

 mining magnetic rotations, and having determined the influence 

 of temperature and dissolution on this property, gives the results 

 of the examination of a large number of compounds of different 

 types. Great differences exi.st between the magnetic rotations 

 of aromatic and fatty compounds, the nuclei contained in a 

 substance considerably influencing its rotation ; frequently the 

 compounds behave as composite molecules, the fatty and cyclic 

 part separately influencing the magnetic rotation ; the presence 

 of a carbonyl group connecting the nucleal and fatty groups 

 seems to act as a screen, preventing them from influencing each 

 other. The influence of the nucleus on the rotation is reduced 

 by the presence of electro-negative groups, and increased by that 

 of electro-positive ones ; this great liability of the magnetic 

 rotation of the nucleus to change, is connected with the fact of 

 its unsaturatedness, for saturated cyclic compounds behave like 

 oidinary open chains. The so-called values given for atomic 

 refractions or magnetic rotations are not true physical constants, 

 but are merely the average influences which elements or radicles 

 exert in different compounds ; this, however, does not detract 

 from their usefulness in determining constitution. — Mononitro- 

 guaiacol, by R. Meldola. One mononitro-derivative, probably 

 the para-compound, is obtained by nitrating acetylguaiacol ; 

 benzoylguaiacol yields two mononitro-derivatives, probably the 

 ortho- and para-, on nitration. Mononitroguaiacol may be pre- 

 pared by hydrolysing its acetyl-derivative. 



Linnean Society, June 4. — Anniversary Meeting. — Mr. 

 C. B. Clarke, F.R.S., President, in the chair.— The Gold 

 Medal of the Society was formally awarded to Prof. G. J. 

 Allman, F. R.S. , for distinguished researches in zoology, and, 

 in consequence of his inability to receive it in person, w.as 

 delivered on his behalf to Sir Joseph D. Hooker, K.C.S.I., 

 who made a suitable acknowledgment. The Treasurer then 

 presented his annual statement of accounts. The Secretary 

 reported the deaths, withdrawals, and elections during the past 

 year. The report of the Librarian having been read, the 

 President opened the chief business of the evening, when the 

 Fellows present proceeded to ballot for the President, Officers, 

 and Council for the ensuing year. Scrutineers having been 

 appointed, and the votes counted, the result was declared to be 

 as follows : — President, Dr. Albert (junther, F. R.S. ; Treasurer, 

 Mr. Frank Crisp ; Secretaries, Mr. B. Daydon Jackson and 

 Prof. G. B. Howes. The retiring President, Mr. C". B. Clarke, 

 then delivered the annual presidential address, which on the 

 motion of Mr. W. Carruthers, seconded by Mr. W. P. Hiern, it 

 was resolved should be printed and circulated. 



Mathematical Society,June 11. — Major MacMahon, R..\ , 

 F. R.S. , President in the chair. — The Chairman announced that 

 the Council had awarded the De Morgan Memorial Medal to 

 Mr. >S. Roberts, F. R. S. He also read an address which the 

 Council had requested him to present to Lord Kelvin on the 

 occasion of the jubilee celebration on the l6th instant. The 

 address, which was illuminated, was placed for inspection on 

 the table. The following communications were made : — Waves 

 in canals, by H. M. Macdonald ; on the a, h, c form of the 

 binary quintic, by J. Hammond ; construction for the four 

 normals to a central conic drawn through a given point, by Prof. 

 Mathews; on a two-fold generalisation of Stieltjes' theorem, 

 by Dr. Taber ; notes on magic squares, by Rev. A. H. Frost. 



Entomological Society, June 3.— Dr. D. Sharp, F. R.S. , 

 Vice-President, in the chair. — Mr. Gervase F. Mathew exhibited 

 the new species of Leucania, L. flaviiolor, recently described by 

 Mr. Barrett (Eiit. Monthly Mag., 2nd series, vol. vii. p. 99), 

 and also the varieties of/.. /a//cv;.r noticed by Mr. Barrett in the 

 same article (/. <■. , p. 100). Mr. Tutt having carefully examine<l 

 the specimens of Leucania flavicolor, said that he considered it 



