214 



NATURE 



[June 26, 1890 



■made to investigate the relative plasticity of pure ice at various 

 temperatures ranging down to - 35° F., and also of pond ice. 

 The arrangements of apparatus used in determining the plasticity 

 of pure ice and pond ice are illustrated in detail in the paper. The 

 ice for the pure ice experiments was frozen from distilled water ; 

 the coolest freezing mixture used, consisting of three parts by weight 

 of crystallized calcium chloride and two parts by weight of snow, 

 yielded a constant temperature of - 35° F. ; other freezing mix- 

 tures were used for the temperatures above this. The cylinders 

 of pure ice employed were 2 feet \\ inch long, and 2 feet \\ 

 inch diameter, and weighed 470 pounds. The plasticity was 

 ascertained by measuring the relative penetration, during equal 

 periods of time, of the polished steel rods into the ice, care being 

 taken to avoid errors from conductivity. A large number of ex- 

 periments were also made on the plasticity of natural lake or 

 pond ice. The influence of the composition of water on the 

 plasticity of the ice frozen therefrom was investigated, and a 

 ■number of experiments were made to ascertain the proportion of 

 Ihe saline constituents of the lake water taken up into the ice 

 during crystallization. Roughly speaking, it was found that the 

 proportion of inorganic matter in the melted ice was about ten 

 per cent, of the total inorganic salts contained in the lake water 

 from which it was frozen. The general summary of results of 

 the experiments on the plasticity of pure ice at the various tem- 

 peratures employed are plotted out in four curves on Diagram I. , 

 and the results of the experiments on the plasticity of pond ice 

 are shown in detail on Diagram II. In the majority of in- 

 stances, it was found that, if the plasticity of the ice at - 35° F. 

 be called i, at o" F. it would be about twice as much, and at 28° F. 

 the plasticity would be about four times as great as at 0° F., or 

 eight times as much as at - 35° F. The comparatively great 

 contractibility in ice observed at considerably reduced tempera- 

 tures (see the author's former paper " On Observations on Pure 

 Ice and Snow," Roy. Soc. Proc, No. 245, p. 544) may prob- 

 ably account for the great reduction in its plastic properties at 

 low temperatures. This is in accord with the practical cessation 

 of motion in glaciers during the cold of winter. I^ was also 

 noticed in course of the research that the plasticity of the 

 naturally frozen pond ice was manifestly greater than that of the 

 prepared pure ice ; the comparative difference in the behaviour 

 of the pond ice was doubtless owing to a portion of the saline 

 constituents of the water interspersing during congelation 

 between the faces of the individual crystals of ice, thereby tend- 

 ing to reduce the cohesion of the mass as a whole, and increasing 

 its plasticity. 



Linnean Society, June 5. — Prof. C. Stewart, President, in 

 the chair. — The President nominated as Vice-Presidents for the 

 year Messrs. W. Carruthers, P. Martin Duncan, J. G. Baker, and 

 F. Crisp. — Mr. H. Little exhibited and made some remarks upon 

 a photograph of a remarkable Aroid, Amorphophallus titanum, 

 which had flowered for the first time in this country. — Mr. 

 James Groves exhibited a specimen of an Orobajtche parasitic 

 upon a Pelargoniu7ti. — The following papers were then read and 

 discussed : — On a collection of plants made in Madagascar, by 

 Mr. G. F. Scott Elliot. — On Weismann's theory of heredity 

 applied to plants, by Rev. G. Henslow. — Teratological evidence 

 as to heredity of acquired conditions, by Prof. Windle. — On 

 the development of the tetrosporangia in Rhabdochorton Rothii, 

 Naegeli, by Mr. Harvey Gibson. — On the position of Chan- 

 transia, with a description of a new species, by Mr. George 

 Murray and Miss E. Bass. — On the development of the cystocarp 

 in Callophyllis laciniata, by Miss A. L. Smith. — On the cysto- 

 carps of some genera of Floridese, by Mr. J. B. Carruthers. 



Royal Meteorological Society, June 18. — Mr. Baldwin 

 Latham, President, in the chair. — The following papers were 

 read : — On the difference produced in the mean temperature 

 derived from daily maximum and minimum readings, as depend- 

 ing on the time at which the thermometers are read, by Mr. W. 

 Ellis. In the publications issued by the Greenwich Observatory 

 authorities, the maximum and minimum temperatures are those 

 referring to the civil day from midnight to midnight. At many 

 stations the observers only read their instruments once a day, 

 viz. at 9 a.m., when the reading of the maximum thermometer 

 is entered to the preceding civil day, and the reading of the 

 minimum thermometer to the same civil day. Such stations are 

 called " climatological stations." The author has tabulated 

 the Greenwich maximum and minimum temperatures according 

 to both methods for the years 1886-89, and finds that the clima- 

 tological maximum and minimum means are in excess of the 



NO. 1078, VOL. 42] 



civil day means. — On the distribution of barometric pressure at 

 the average level of the hill stations in India, and its probable 

 effect on the rainfall of the cold weather, by Mr. W. L. Dallas. 

 The weather over India during January 1890 was very dry, and 

 in marked contrast to that which prevailed during January 

 1889. The distribution of barometric pressure was, however, 

 much the same in both months. The author has investigated 

 the records at the hill stations, and has prepared charts showing 

 the distribution of barometric pressure from both high and low 

 level stations. From the high level charts it appears that the 

 mean barometric gradient in 1889 was rather more than twice 

 that in 1890, and, considering what is known of air movements, 

 even at moderate elevations above the earth's surface, it may be 

 assumed that these differences in pressure were accompanied 

 with large differences of air motion ; and if it is also a'^sumed 

 that the evaporation over the Southern Ocean is in all years 

 fairly comparable in amount, the deficiency of rainfall over 

 India in the winter of 1889-90 can be attributed to diminished 

 lateral translation of vapour owing to sluggish movements in the 

 upper atmosphere. — On the relative prevalence of different 

 winds at the Royal Observatory, Greenwich, 1841-89, by Mr. 

 W. Ellis. The author gives the following as the average number 

 of days of prevalence of different winds for the 49 years 1841-89, 

 as derived from the records of the self-registering Osier anemo- 

 meter : — 



N. N.E. E. S.E. S. S.W. W. N.W. Calm. 



40 45 27 22 35 106 46 22 22 



— On some recent variations of wind at Greenwich, by Mr. A. B. 

 MacDowall. — On the action of lightning during the thunderstorms 

 of June 6 and 7, 1889, at Cranleigh, by Captain J. P. Maclear, 

 R.N. The author examined a number of trees which had been 

 struck by lightning during these thunderstorms, and found that 

 those which were struck before the rain fell were shattered, 

 while those which were struck after the rain commenced were 

 simply scored, with the bark blown off. It seems that during 

 rain every tree is conducting electricity, and a disruptive dis- 

 charge takes place where the conductor becomes insufficient. 

 This depends on the position of the cloud, the amount of foliage 

 on the tree, its condition of moisture, and its connection with 

 running water. 



Geological Society, June 4.— Dr. A. Geikie, F.R.S., Pre- 

 sident, in the chair. — The President referred to the sad Inss 

 which the Society had sustained through the death of Mr. 

 Dallas, and read the following resolution, which had been 

 passed by the Council and ordered to be entered upon its 

 minutes: — "The Council desires to record on its minutes an 

 expression of its deep regret at the death of the Assistant- 

 Secretary, Mr. Dallas, which took place on the 29th ultimo, 

 and of its sense of the loss inflicted on the Council and Society 

 by the removal of one who, for the long period of twenty-two 

 years, had done them invaluable service, and who, by his 

 courtesy, kindliness, and helpfulness had endeared himself as 

 a personal friend to the Fellows." It was moved by Dr. Evans, 

 seconded by Dr. Hinde, and carried unanimously, that the reso- 

 lution passed by the Council be communicated to Mrs. Dallas 

 on behalf of the Society also. — The following communications 

 were read : — As to certain " changes of level " along the shores 

 on the western side of Italy, by R. Mackley Browne. — North 

 Italian Bryozoa, by A. W. Waters.— Notes on the discovery, 

 mode of occurrence, and distribution of the nickel- iron alloy 

 j " Awaruite," and the rocks of the district on the West Coast of 

 the South Island of New Zealand in which it is found, by Prof. 

 G. H. F. Ulrich. In an introduction, the author describes the 

 original discovery, determination, and naming of the mineral 

 in 1885 by Mr. W. Skey, and clears up a misunderstanding by 

 which he himself had been credited with the discovery ; he 

 furthermore gives a historical sketch of the further investigations 

 and publications refeiring to the mineral. The geology of the 

 Awaruite-bearing district is described. The rocks consist of 

 peridotites and serpentines, breaking through metamorphic 

 schists with occasional massive intrusions of acid rock. The 

 petrographical characters of the peridotites of the hill-complex, 

 including the Olivine and Red Hill Ranges, and serpentines are 

 considered in detail, and the mode of occurrence of the Awaruite 

 in them and in the sands derived from their denudation is dis- 

 cussed. The author submits a sketch-map of the localities 

 where the mineral has been discovered in sand, including not 

 only George River, but also Silver Creek, Red Hill, and other 

 localities, and quotes Mr. Paulin's belief that it occurs diffused 



