Jan. 24, .1889] 



NATURE 



3'i 



adopted, the President delivered an address on " Fogs," which 

 he illustrated by a number of interesting lantern slides. Fogs 

 and clouds are one and the same thintj. A cloud is a fo^; when 

 entered into, and a fog seen from a distance, suspended in the 

 air, becomes a cloud. After describing the various kinds of 

 fc^ — e.g. river, sea, Newfoundland, radiation, town, «S:c., fogs — 

 Dr. Marcet referred to London fogs. Dr. Tyndall has accounted 

 for them by assuming each particle of condensed vapour t3 be 

 covered by coal smoke. These fogs usually accompany a high 

 barometer, and are frequently dry in their chp.racter. It is a 

 well-known fact that cold air on the tops of hills, being heavier 

 than the air below, slides down the slopes, so that the lower 

 parts of the hillsides are actually colder than the plains at some 

 distance from the hills. Now, London, in the Thames Valley, 

 is surrounded by hills— to the north, Highgate, Hampstead, and 

 Harrow ; in a westerly direction. Putney and Wimbledon ; and 

 in a more southerly direction, Clapham and Sydenham. The 

 air is colder on these hills than in London with its millions of 

 inhabitants, its coal-fires and factories, hence it is heavier, and 

 will have a great tendency to slide down the hills towards the 

 town and the river. Should the air in town be on the point of 

 saturation, and the cold air from above saturated with vapour, 

 it is obvious that the increased cold from above will produce 

 a precipitation of moisture, and it will come to pass that a fog 

 is produced. If the hill-tops be not only colder than the air 

 below, but enveloped in a fog, it stands to reason that the fog 

 below will be all the denser, and especially in the neighbour- 

 hood of water, such as the River Thames and the ornainental 

 waters in the parks. — The following gentlemen were elected the 

 officers and Council for the ensuing year : — President : Dr. Wm. 

 Marcet, F.R.S. Vice-Presidents: Francis Campbell Bayard, 

 Henry Francis Blanford, F.R.S., William Ellis, Richard Inwards. 

 Treasurer : Henry Perigal. Trustees : Hon. Francis Albert Roilo 

 Russell, Stephen William Silver. Secretaries : George James 

 Symons, F.R.S., Dr. John William Tripe. Foreign Secretary : 

 Robert Henry Scott, F.R.S. Council: Edmund Douglas 

 Archibald, William Morris Beaufort, Arthur Brewin, George 

 Chatterton, William Henry Dines, Frederic Bernard Edmonds, 

 Charles Harding. Baldwin Latham, Capt. Tohn Pearse Maclear, 

 R.N., Edward Mawley, Henry Southall, Dr. Charles Theodore 

 Williams. 



Zoological Society, January 15.— Prof. Flower. F.R.S., 

 President, in the chair.— The Secretary read a report on the 

 additions that had been made to the Society's Menagerie during 

 the month of December 18 8, and called attention to the young 

 Chimpanzee purchased of .Mr. Cross, of Liverpool, on December 

 6 (see N.vruRK of January 10, p. 254).— A letter was read 

 from Heer F. E. Blaauw, of Amsterdam, containing an account 

 of the devel.)pment of the horns of the White-failed Gnu as 

 observed in specimens bred in his menagerie. — Prof. Newton 

 exhibited a specimen of Pcnuula tiiilbi. Dole, brought from the 

 Sandwich Islands by Mr. S. B. Wilson, remarking that it 

 seemed to be identical specifically with Kalltis tibscnnis, Gmelin, 

 a species which has not been lately recognized.— Prof. Bell made 

 sotne remarks on the question of the food of Bipalitan. —Ca.non 

 Tristram made some remarks on a specimen oi EviOeriza cioides 

 a Bunting of Siberia, of which a specimen was believed to have 

 been obtained in this country at Flamborough in October 1887. 

 —Prof. F. Jeffrey Bell read a note on the Echinoderm fauna of 

 the Bay of Bengal.— Mr. F. E. Beddard and Mr. Frederick 

 Treves gave an account of the anatomy of the Sumatran 

 Rhinoceros as observed in two specimens of this animal that 

 had lately died in the Society's Gardens. The muscular anatomy 

 of the limbs of this Rhinoceros was especially treated of. — Prof. 

 Newton read a paper on the breeding of the Seriema (Cariam'a 

 cris/ata) in the Society's Gardens. 



Entomological Society, January 16 — Fifiysixth Anni- 

 versary Meetmg.— Dr. D. Sharp, President, in the chair.— An 

 abstract of the Treasurer's accounts, showing a Iwlance in the 

 Society's favour, was read by Mr. Osbert Salvin, F.R.S., one 

 of the auditors ; and Mr. H. Goss read the Report of the Council. 

 It was announced that the following gentlemen had been elected 

 as officers and Council for 1889 .- — President : The Right Hon. 

 Lord Wnlsingham, F.R.S. Treasurer: Mr. Edward Saunders. 

 Secretaries: Mr. Herbert Goss and the Rev. Canon Fowler! 

 Librarian : Mr. Ferdinand Grut. And as other members of 

 Council, Mr. Henry W. Bales, F.R.S., Capt. 11. J. Elwes, Mr. 

 William H. B. Fletcher, Mr. F. DuCane Godjjan, F.R S 

 Prof. Raphael Meldola, F.R.S., Dr. P. B. Mason, Mr. O^bcrt 



Salvin, F.R.S., and Dr. I). Sharp.— Dr. Sharp, the outgoing; 

 President, then delivered an address, for which a vote of thanks- 

 to him was moved by Capt. Elwes, seconded by Mr. Salvin, and 

 carried. A vote of thanks to the Treasurer, Secretaries, anc> 

 Librarian was moved by Mr. J. W. Dunning, seconded by Lord 

 Walsingham, and carried. Mr. Saunder-, Mr. Goss, and Mr. 

 Grut severally replied. 



Paris. 

 Academy of Sciences, January 7.— M. Janssen in the chair. 

 —On the l.indstedt series, by M. H. Poincare. Although these 

 series are not convergent in the strict sense of the word, they are 

 often very useful in astronomical calculations owing to the rapidity 

 with which the terms decrease. Here M. Lindstedt's method is 

 presented from a fresh standpoint, and brought into connection 

 with the principles expounded in Jacobi's " Vorlesungen liber 

 Dynamik." — On the reactions between chromic acid and oxygen- 

 ated water, by M. Berthelot. This peculiar reaction has acquired 

 a fresh interest since M. Ad. Carnol's recent discovery of an 

 ingenious method for effecting the quantitative analysis of chromic 

 acid by means of oxygenated water, and reciprocally, with 

 simultaneous reduction of both compounds. The analogy of the 

 reaction with that of permanganic acid has induced M. Berthelot 

 to repeat the experiments, with the result that this, like other 

 reactions of oxygenated water, may now be interpreted by the 

 laws of thermo-cheniistry. — On an hydraulic machine constructed 

 in England, by M. Anatole de Caligny. The reference is to 

 Mr. Pearsall's apparatus, in which M. de Caligny's open tube is 

 replaced by a chamber allowing the air to escape freely. — Ob- 

 servations made on the summit of Mont Ventoux on the calorific 

 intensity of .solar radiation, by MM. A. Crova and Houdaille. 

 The object of these observations has been to ascertain whether, 

 at an altitude of 1900 metres, solar radiation undergoes daily 

 variations analogous to those recorded at Montpellier, and 

 whether from the curves registered at the higher elevation a 

 value may be deduced for the solar constant more exact than 

 those obtained from the calculation of the curves traced at sea- 

 level. It results from these researches that at the altitude of 

 1900 metres the solar constant may acquire a value very close to- 

 the 3 calories obtained by Mr. Langley from his observations- 

 on Mount Whitney. The polarization of the blue light of the 

 sky was also studied by means of M. Comu's photopolarimeter, 

 and its spectrum analysis made with M. Crova's spectrophoto- 

 meter modified for the purpose. The polarization appears in 

 general to increase with the solar constant, thus furnishing useful- 

 data for determining the degree of calorific transparency in the 

 atmosphere. — On the true and mixed butylic ethers, by M. ¥.. 

 Reboul. Theory anticipates ten of these compounds ; but two 

 only are known, the normal diprimary butylic ether of Lieben 

 and Rossi, and Kessel's di-econdary. W'iliianson's general 

 method having mostly failed, or yielded only doubtful results, M. 

 Reboul has attempted by the process here described to complete- 

 the whole series. He has so far obtained five, not yet described, 

 which with the two already known leave three to be still 

 procured under other conditions. — On M. Hirn's new work, 

 entitled "Constitution de I'Espace celeste," by M. Faye. This- 

 important work deals with the question of an ether or subtle 

 medium filling all space, as postulated by physicists to explain the 

 phenomena of light, heat, and electricity, but the presence of whicb 

 astronomers have failed to detect as a resisting medium in the 

 movements of the heavenly bodies. With a view to putting Ihis- 

 seeming contradiction in a clear light, M. Hirn has worked out 

 some delicate calculations which have led to several remarkable 

 and at times wholly unexpected conclusions. Thus in estimating 

 the density of a new medium capable by its resistance of causing 

 a secular acceleration of half a secind in the mean velocity of the 

 mo m, he finds that such a density would correspond with a 

 kilogramme of matter uniformly diffused th-oughout a space of 

 about 390,000 square miles. This is a density one millim times^ 

 rarer than that of the air reduced to one millionth of its norma) 

 density in Mr. Crookes's ingenious apparatus. — On the perturba- 

 tions of the planet Hestia (46), according to the theory of M. 

 Gylden, by M. Brendel. The application of M. Gylden'slheiry 

 of perturbations to this planet shows that it is subject to some 

 very considerable disturb.inces, its mean motion being about 

 three times that of Jupiter. — On a process by which diurnat 

 nutation may be demonstrated, and its constants determined, by 

 M. Fo ie. This extremely simple process consists in observing^ 

 at intervals of six hours two stars distant not more than 3' from 

 the Pole. — On the quantitative analysis of organic nitrogen by the- 

 Kjeldahl method, by M. L. L'Hote. This new method is here 



