286 



NATURE 



[April 28, 192 1 



that deactivated silica is vitreous. A vitreous solid, 

 like a crystal, is probably a polymer. Activation is 

 considered to be the eHect of disrupting the solid 

 polymers. — N. K. Adam : The properties and mole- 

 cular structure of thin films of palmitic acid on water. 

 Part i. Langmuir's views have been confirmed and 

 extended. Films on water exhibit a resistance to 

 lateral compression commencing at 22x10-'* sq. cm. 

 per molecule, and increases linearly with reduction 

 of area until the force is sufficient to buckle the film. 

 Collapse then sets in, and no further increase of force 

 is regularly found necessary to diminish the area to 

 zero. A metastable condition of increased resistance 

 to collapse may occur. The compression curves point 

 to the resistance being due to repulsion between the 

 insoluble molecules, arranged in a single layer on the 

 surface, each molecule being attracted to the water 

 by its carboxyl group. When collapse of the uni- 

 molecular film occurs, the molecules ejected are seen 

 to aggregate into fine lines many molecules in thick- 

 ness. The observed areas agree with the dimensions 

 calculated from molecular volume studies, and the 

 compressibility of the films is of the same order as 

 for liquids in bulk. The efTect of acidity of the water 

 on' the films may be due to the greater attraction of 

 alkaline solutions than acid for carboxyl groups. The 

 observations indicate that the molecules are immersed 

 further in alkaline than in acid solutions, even when 

 alkalinity is insufficient to cause complete solution. 

 In still more alkaline solutions immersion becomes 

 complete, and the molecules probably pass from the 

 film into aggregates, having the hydrocarbon chains 

 in the centre and the carboxyl groups on the surface. 

 This structure is suggested for the "ionic micelle" 

 of soap solutions. — E. P. Metcalfe and B. Ven- 

 katesactaar : The absorption of light by electrically 

 luminescent mercury vapour. Mercury vapour at low 

 pressures, rendered luminous by the passage of small 

 electric currents, exerts powerful selective absorption. 

 A list of wave-lengths found to be absorbed is given. 

 Photometric observations are recorded on the absorp- 

 tion and emission of 5461 A. by columns of mercury 

 vapour of different lengths and carrying different cur- 

 rents. The relation between the ratio (emission/ 

 absorption) and the current density is linear. The 

 lines 5461 A. and 4359 A. have been reversed so as to 

 appear dark lines on the white-light spectrum of a 

 carbon arc and of the sun. The reversal of 5461 A. 

 has been studied in detail. 



Zoological Society, April 19. — Sir S. F. Harmer, 

 vice-president, in the chair. — Mrs. J. Longstafl : Ob- 

 servations on the habits of the snail, CoMitoma 

 zebra, var. fulgurata, and C. zebra, var. obesa, 

 Pfeiffer, in confinement. — R. I, Pocock : The external 

 characters and classification of the Procyonidae (rac- 

 coons, etc.). — Dr. M. A. Smith : New or little-known 

 reptiles and batrachians from southern Annam (Indo- 

 China). 



Royal Meteorological Society, April 20. — Mr. R. H. 



Hooker, president, in the chair. — C. E. P. Brooks : 

 The evolution of climate in north-west Europe. Com- 

 mencing with the last (Wiirmian) Glacial period, the 

 slow variations of climate in north-west Europe are 

 studied in connection with changes in the- land and 

 sea distribution, and also with possible astronomical 

 influences. Several successive "phases" are distin- 

 guished : — (i) The close of the Glacial period, 30000- 

 18000 B.C. (2) The retreat of the glaciers, 18000- 

 6000 B.C. (3) The continental phase, about 5000 B.C. 

 (4) The maritime phase, about 4000 B.C. (5) The 

 forest phase, about 3000 B.C. (6) The peat-bog phase, 

 about 500 B.C. (7) The recent phase. Charts are 



NO. 2687, VOL. 107] 



drawn to illustrate the probable meteorological condi- 

 tions associated with each of these phases, and 

 especially the gradual development of the present 

 system of storm-tracks, the Mediterranean being the 

 oldest. The cessation of the peat-bog phase is shown 

 to be contemporaneous with a marked drop in 

 Huntington's curves of rainfall in California and 

 south-western Asia. The whole series of changes in 

 north-west Europe is compared with the correspond- 

 ing post-Glacial series in North America, which is 

 shown to be similar in its general lines, but not 

 always contemporaneous. Finally, a section is devoted 

 to Pettersson's astronomical tidal theory, which is 

 found to fit in very well with the changes after 

 3000 B.C., but not before. — Lieut. G. C. Steele : A brief 

 review of the influence of meteorology on naval war- 

 fare. In almost every action fought in the late war 

 some reference was made to the state of the weather. 

 The last five years have seen new acquisitions to 

 naval service, most notably the C.M.B., a naval air 

 wing, and such weapons as the smoke screen^ and 

 even the possibility of the use of poisonous gas at 

 sea. Analysing the effect of meteorological conditions 

 on these new arms, the last two are seen to be con- 

 tingent on weather conditions, and the others are so 

 in a large degree. Modern invention has thus not 

 overcome the influence of meteorology on naval war- 

 fare. Its influence can be traced also in the policy 

 of ship construction. For example, in a programme 

 of shipbuilding the general climatology of the sea 

 or ocean forming the probable theatre of war in a 

 great measure determines the gun-range at which an 

 action will be fought, and, consequently, the amount 

 of armour to be allocated under these conditions. 



Paris. 



Academy of Sciences, April 4. — M. Georges Lemoine 

 in the chair. — The president announced the death of 

 M. ValHer, correspondant of the Academy. — E. L. 

 Rouvier : A work relating to the French fauna. 

 Remarks on a memoir on Echinoderms by R. Koehler, 

 published by the French Federation of Natural Science. 

 — G. Gouy : The calculation of the coma. The calcula- 

 tions in a recent note assumed that the aberration on 

 the axis of the lens is zero. A first approximation is 

 now given for the case when the aberration is sensible. 

 — M. Lugeon : A new example of striation of a river- 

 bed. The Lower Ard^che, between Vallon and Saint- 

 Martin, presents striations resembling those of the 

 banks of the Yadkin, in North Carolina, described by 

 the author in 19 13.- — G. Julia : A functional differen- 

 tial equation analogous to Hadamard's equation. — A. 

 Denjoy : The determination of functions presenting .a 

 certain complex character of solvability. — T. Vara- 

 poulos : The theorem of Landau and multiform func- 

 tions. — F. Carlson : The series of Dirichlet. — H. 

 Godard : Observations of the Reid comet made at the 

 Observatory of Bordeaux (38-cm. equatorial). The 

 apparent positions and the positions of the comparison 

 stars are given for March 30 and 31 and April i. The 

 comet was about 105 magnitude on March 31. — P. 

 Chofardet : Observations of the Reid comet (1921a) 

 made with the coude equatorial at the Besan(;on Ob- 

 servatory. Positions given for March 30 and 31 and 

 April I. — J. Guillaume : Observations of the Reid 

 comet made with the coud^ equatorial at the Observa- 

 tory of Lyons. Positions given for March 28, 30, and 

 31. The comet is circular, less than i' in diameter, 

 with a central condensation ; mag^nitude 9-5. — C. E. 

 Brazier : The comparability of anemometers. A direct 

 comparison in the open air of eight tvpes of anemo- 

 meters, all previously well standardised in the labora- 

 tory, showed that unless the inclination of the com- 



