426 



NA TURE 



[March i, 1894 



than usual, or, if the temperature is rising, to check the rise ; 

 but any sudden variation is very rare. The rainfall is not great, 

 though it is spread over a large number of days, the average 

 yearly amount being 8-90 inches. The greater part of the rain 

 falls during October to January, while the period from June to 

 September is practically rainless. — Report on the phenological 

 observations for 1893, by Mr. E. Mawley. This was a discussion 

 of the observations made on the flowering of plants, appearance 

 of insects, and the song and nesting of birds. The year 1893 

 was in complete contrast to its predecessor, being very forward 

 throughout the United Kingdom. The February and March 

 Dlants were later than usual in blossoming, especially in the 

 colder parts of our Islands, but after this the dates were every- 

 where in advance of the average, and during the height of the 

 flowering season the departures from the mean were often con- 

 siderable. — Comparative observations with two thermometer 

 screens at Ilfracombe, by Mr. W. Marriott. Some exception 

 having been taken to the thermometer screen which has been 

 in use at Ilfracombe for a num.ber of years past, a Stevenson 

 screen was placed at a distance of 60 feet from the old screen 

 in October, 1892, since which date simultaneous observations 

 in the two screens have been made daily at 9 a.m. The results 

 of this comparison show that the temperature deduced from the 

 two sets of observations agrees very closely, the old screen being 

 only o°'3 higher than the Stevenson. 



Cambridge. 



Philosophical Society. — February 12.— Prof. Hughes, 

 President, in the chair. — On a suggested case of mimicry in the 

 moUusca, by Mr. A. H. Cooke. The species concerned were 

 Strombiis iitattriiianus, L., and S. lulmaniis, L., the shells of 

 which diftered from those of all other Stronibus in their close 

 resemblance to the shell of Coims, a genus with which they are 

 known to live : Strombus being a frugivorous animal with small 

 and weak teeth, and Comes on the other hand being carnivorous, 

 with very large and barbed teeth, provided with a poison bag 

 and duct. It was suggested that this resemblance must tend 

 greatly to the advantage of the Strcmhiis, since the dangerous 

 properties of Conns would tend to prevent its being touched by 

 predatory fishes. — On the evidence as to the extent of earth move- 

 ments and its bearing upon the question of the cause of glacial 

 conditions, by the President. Prof. Hughes referred to the former 

 paper in which he discussed the first part of the question, viz. the 

 evidence of glacial conditions offered by scratched stones and 

 smoothed and striated rock surfaces. He then stated the second 

 part of the question in the same form as that in which the astro- 

 nomical theory of the cause of recurrent glacial conditions is 

 usually put forward. He contended that there is abundant 

 evidence of contemporary earth movements of such a kind and 

 magnitude as would, if their possible effects were not destroyed 

 or modified by other causes, produce greater vicissitudes of 

 temperature than any that are required to explain the most ex- 

 treme glacial conditions observed in past time. An examina- 

 tion of the succession of events as recorded in the crust of the 

 earth shows that these greater movements of elevati' n and de- 

 pression have been secularly recurrent, and an inquiry into the 

 geographical distribution of the formations which are held to 

 contain evidence of glacial action leads to the conclusion that 

 they are arranged round basins, and further that around the rim 

 of these basins we have the clearest proofs from independent 

 evidence of marginal movements of great intensity. The 

 average fall of temperature as we ascend is observed to be about 

 1° F. for every 300 feet. Therefore the reduction of tempera- 

 ture due to such elevations as would result from known up- 

 heavals is quite sufficient to explain the occurrence of glaciation 

 anywhere. A consideration of the geographical causes of glacial 

 conditions explains why the effect has not always followed 

 when the upheaval is known to have been great enough to have 

 produced it : seeing that it is along the axes and areas of 

 greatest movement that the greatest denudation takes place and 

 the actual elevation represents only the excess of uplift over 

 denudation. — On the fertilisation of some species of Medicago in 

 England, by J. H. Burkill. The floral mechanism of four species 

 of Medicago {saliva, L., falcata, L,., silvestris. Fries, and /?</«■ 

 hna, L., was discussed, and lists of insect-visitors given. The 

 processes which unite the alae and carina hold thestaminal tube in 

 position in the unexploded flower, while the basal processes of 

 the alae serve as triggers whereby an insect may explode it. 

 The stigma is rendered fertile by rubbing as in Lotus, but in 

 M. lupidina in older unexploded flowers becomes receptive and 



NO. T270, VOL. 49] 



self-fertilised. Flies form a larger percentage of the insect- 

 visitors in England than in Germany. — Contributions to the 

 geology of the gosau beds of the Austrian Salzkatnmergut, by 

 H. Kynaston. 



Edinburgh. 



Royal Society, February 5. — Prof. Copeland, Astronomer 

 Royal for Scotland, in the chair. — Dr. John Murray gave an 

 address on the floor of the ocean at great depths. He discussed 

 the character of the deposits and the organisms found at the sea- 

 bottom by the C/^rt//^«^^;- expedition. Exclusive of iht protozoa, 

 certain species were found in Antarctic waters which corre- 

 sponded to species found in Arctic waters, while no such species 

 were found in intervening tracts. This may be supposed to have 

 been due to the production of the same species, from different 

 origins, under the same conditions ; but it is more in accord- 

 ance with modern ideas to suppose that they had a common 

 origin. Dr. Murray suggested that the common origin was 

 referable to a period when the whole ocean had a fairly uniform 

 high temperature of perhaps 70° or 80". Under this condition 

 there might have been a universal fauna. As the polar regions 

 became colder, similar portions of the fauna became adapted to 

 the like conditions of the northern and southern tracts ; while 

 the portion which was forced to retreat from the colder regions 

 was now represented by the fauna of the coral reefs and tropical 

 waters. 



February 19. — Sir Douglas Maclagan, President, in the chair. 

 — Mr. John Aitken read the third part of a paper on the number 

 of dust-particles in the atmosphere of certain places in Great 

 Britain and on the continent. Observations had been taken at 

 Hyeres, Cannes, and Mentone. There the air was never found 

 to be very pure, the lowest number of dust-particles recorded 

 being 600 per cubic centimetre. At the Italian lakes the con- 

 ditions were found to be somewhat similar. When the wind 

 blew up the slopes from the valleys, the number of dust-particles 

 was greater than when it blew across the mountain tops. On 

 the Righi it was also found that the air from the mountain was 

 purer than the air from the plains. The haze increased with the 

 number of particles. A connection was also observed between 

 the amount of dust and the appearance of the sunset. When 

 there was much dust, the light was warm and soft ; when there 

 was little, the lighting on the landscape was cold, clear, and 

 sharp. A careful series of observations had also been taken at 

 Kingairloch, which, along with others, had been used in the 

 determination of constants in equations connecting the haze with 

 number of dust particles, &c. — A paper, by Mr. George 

 Romanes, containing a suggestion as to the probable nature of 

 electrification, was communicated. 



Paris. 



Academy of Sciences, February 19. — M. Loewy in the 

 chair. — On linear equations .of the second order containing an 

 arbitrary parameter, by M. Emile Picard. — On certain develop- 

 ments in series, required in the theory of the propagation of 

 heat, by M. H. Poincare. — Typhoid fever in Paris, for the 

 period 1 884- 1893 ; its autumn and winter increase. An abstract 

 of a memoir, by M. de Pietra Santa, giving his conclusions con- 

 cerning the general decrease of this disease and the causes of 

 this decrease. — Observations of the new planet AV (Courty, 

 1894, February li), made at the Paris Observatory, by M. G. 

 Bigourdan. — Observations of the planet 1894, AV, made by the 

 great equatorial of the Bordeaux Observatory, by MM. L. 

 Picart and F. Courty. — Results of the solar observations made 

 at the Royal Observatory of the Roman College during the fourth 

 quarter. of 1893, by M. P. Tacchini. — On the tetrahedra conju- 

 gate with respect to a quadric, and of which the edges are tan- 

 gents to another quadric, by M. H.Vogt. — On a case of degenera- 

 tion of a general projective system, by M. F. Engel. — On the 

 movement of two points joined by a spring, by M. L. Lecornu. 

 — On a system of two pendulums joined by an elastic thread, by 

 M. Lucien de la Rive. — A new simplified method for the calcu- 

 lation of rapidly alternating currents, by M. A. Blondel. — The 

 symmetrical aplanatic objective, by M. Ch. V. Zenger. The 

 author has constructed systems of lenses imitating as far as pos- 

 sible the conditions obtaining in the human eye. He gives the 

 necessary mathematical investigation. Two lenses, a plano- 

 convex lens of phosphate crown glass, and a plano-concave of 

 borate crown glass of less refracting and greater dispersive power, 

 are combined to produce a system for which it is claimed, that(i) 

 the achromatism is exact for the entire length of the spectrum ; 



