November 17, 1910] 



NATURE 



95 



SOCIETIES AND ACADEMIES. 

 London. 

 Royal Society, November lo. — Sir Archibald Geikie, 

 K.C.B., president, in the chair. — Sir George Darwin : 

 <i) The tidal observations of the British Antarctic Expedi- 

 tion, 1907 ; (2) a mistake in the instructions for a certain 

 apparatus in tidal reductions. — F. Soddy and A. J. 

 Berry : Conduction of heat through rarefied gases. — II. 

 The thermal conductivities of argon, helium, and hydrogen 

 at very low pressure have been examined in greater detail 

 with new and improved apparatus. The hypothesis pro- 

 visionally put forward (Roy. Soc. Proc. A, vol. Ixxxiii., 

 1910, p. 254), that the interchange of energy on impact 

 is imperfect in the lighter gases, has been tested and 

 found not to account for the smallness of the ratio (K/Q) 

 of the found to the calculated conductivities. The con- 

 ductivity of hydrogen using a palladium hot w^ire is the 

 same as that with a platinum wire. Change of tempera- 

 ture of the hot surface, that of the cold surface remain- 

 ing constant at room temperature, does not exert so much 

 influence on the value of K as was anticipated. The value 

 of K/Q tended to diminish as the difference of tempera- 

 ture increased, especially at high temperatures. At low 

 temperatures, attained by immersing the apparatus in 

 liquid air and in solid carbon dioxide and ether, the ratio 

 K/Q is diminished, whereas on the hypothesis of imperfect 

 interchange of energy an increase was expected. Jacket- 

 ing the apparatus with vapwurs up to 264° caused an 

 increase in the value of K/Q. It appears that, most prob- 

 ably, increase in the difference of temperature between the 

 surfaces tends to decrease the value of K/Q, whereas in- 

 crease in the temperature of both surfaces increases it. 

 Argon under some of the new conditions tried conforms 

 lo the theory hardly better than the other gases, and the 

 agreement found previously was probably fortuitous. The 

 general conclusion is that the conductivity at low pressures 

 varies less with the nature of the gas and with the tempera- 

 ture of the experiment than is to be expected from kinetic 

 considerations. The extreme values found for the con- 

 ductivities of the three gases over a range of about 450° 

 lay between 08 and 3-4, whereas the calculated values lie 

 between 095 and 16-2 (X 10- * calorie, per sq. cm. of hot 

 surface, per i° difference of temperature, per 001 mm. 

 pressure of gas). — W. H. Hatfield : The chemical physics 

 involved in the precipitation of free carbon from the alloys 

 of the iron-carbon system. The intention of the author 

 is to examine the conditions under which free carbon is 

 produced in iron and steel. Whereas it has been an open 

 question as to whether or not free carbon could be pro- 

 duced direct from the solid solution, the paper is intended 

 to prove the truth of the theory that free carbon can only 

 he produced by the dissociation of the free carbide. It is 

 hoped to demonstrate that this theory holds good through 

 the whole range of the alloys in which free carbon, 

 whether as graphite or annealing carbon, is found. After 

 the presentation of evidence in support of this view of the 

 production of graphite in and near the freezing range, 

 experiments, performed to determine the chemical physics 

 underlying the liberation of annealing carbon in white 

 cast iron, are described. By the electrolytic method of 

 analysis the cementite carbide was obtained from such 

 irons of varying composition, and it is shown how, by 

 varying the percentage of silicon, manganese, or sulphur 

 in the iron, the composition of the cementite is modied 

 and its degree of stability at varying temperatures deter- 

 mined. It is also shown that the size and structure of 

 the precipitated annealing carhop is largely due to the 

 size and structure of the original cementite. Experiments 

 performed to produce annealing carbon in blister steel 

 during the cementation process are then described, after 

 which an explanation of the phenomena of " black " steel 

 is discussed ; it is shown that the free carbon found in 

 'such steels may present one of two formations, each pro- 

 duced under different conditions. The author further 

 endeavours to demonstrate that whilst the free cementite 

 carbide is dissociated at high temperatures through the 

 whole range of the alloys, the carbide remaining in solid 

 solution does not dissociate until the resolution of the solid 

 solution into the carbide and iron of the pearlite, at the 

 carbon change point. — Dr. F. Norton : A spectroscopic 

 investigation of the nature of the carriers of positive elec- 



NO. 2142, VOL. 85] 



tricity from heated aiuminium phosphate. The emission 

 of positive ions from substances heated in a vacuum has 

 been investigated by several experimenters, and it has 

 been found that the ratio of the charge to the mass of the 

 ions is the same for all the substances so far experimented 

 on. .Assuming that the charge is equal to that carried 

 by the hydrogen ion in electrolysis, the mass of the carriers 

 of positive electricity from heated substances must be 

 about twenty-six times that of the hydrogen atom. The 

 object of this research was to obtain the spectrum of these 

 ions. .Aluminium phosphate was chosen for investigation, 

 because of the very large positive ionisation produced on 

 heating this substance. -A calculation showed that, with 

 the apparatus used, it might be expected to collect a 

 sufficient quantity of the carriers to obtain their spectrum 

 in a small vacuum tube. The vessel used to collect the 

 carriers was cooled in liquid air during the passage of the 

 thermionic current from a strip of platinum covered with 

 aluminium phosphate to a surrounding platinum cylinder. 

 The material collected was then allowed to vaporise, and 

 its spectrum was obtained by rendering it luminous with 

 an electrodeless ring discharge. The spectrum of carbon 

 monoxide was always obtained, although precautions had 

 been taken to exclude this gas, or materials which might 

 give rise to it, from the apparatus. It is concluded, there- 

 fore, that the positive ions consist of carbon monoxide, 

 the molecular weight of which agrees fairly well with that 

 required by the results of the e/nt determinations. It is 

 considered improbable that this gas is evolved on heating 

 every substance which has been experimented on in the 

 determinations of the specific charge, but from the nature 

 of the apparatus used it must always have been present 

 during these determinations. In the paper reasons are 

 given for believing that molecules of carbon monoxide 

 readily act as carriers of positive electricity, and this gas 

 probablv diffuses into the hot metal or other substance 

 and is evolved in an ionised state.- — N. Bohr : The deter- 

 mination of the tension of a recently formed water-surface. 

 Arguments in further support of the author's previous con- 

 clusion, that the surface tension does not change sensibly 

 with the time that has elapsed since the surface was 

 formed. — Lord Rayleigrh : .Aerial plane waves of finite 

 amplitude. — -J. J. Manley : Observations on the anomalous 

 behaviour of delicate balances, and an account of devices 

 for increasing accuracy in weighings. — Prof. F. \A . 

 Dyson : The improbability of a random distribution of 

 the stars in space. — G. I. Taylor : The conditions 

 necessary for discontinuous motion in gases. — The Hon. 

 R. J. Strutt : (x) The radium content of basalt; 

 (2) measurements of the rate at which helium is produced 

 in thorianite and pitchblende, with a minimum estimate of 

 their antiquity- 

 Royal Microscopical Society, October 19.— Mr. E. T. 

 Spitta, vice-president, in the chair. — ^J. J. Simpson : 

 Hicksonella, a new gorgonellid genus. The genus is 

 established to include three species, all collected off South 

 Africa. One species was described by Prof. Hickson in 

 1904 under the name of Juncella spiralis, but the author 

 believes that a reference to the genus Juncella is 

 im.possible. The clearing up of the position of this 

 puzzling specimen was facilitated by recent work of the 

 author in his revision of the family of the Juncellids. In 

 addition to Hicksonella spiralis, g.n., he describes H. 

 flagellata, sp.n., and H. capensis, sp.n. — E. Heron-Allen 

 and A. Earland : Some varietal forms of Massilina 

 secans. After referring to several varietal forms that had 

 been previously described, the authors related the finding 

 of numerous specimens of three of these varieties in narrow 

 observation tanks where some gatherings of Foraminifera, 

 made off Selsey Bill, had been placed, and where they 

 multiplied. The conclusion arrived at was that the?e 

 variations were caused b}' the want of sufficient shell- 

 making material, the carbonate of lime in the tanks having 

 been used up, the sea water never having been renewed. — 

 E M. Nelson : A micrometric difficult},-. The author re- 

 ferred to the difficulty of counting correctly the number 

 of ruled lines, or diatomic striae, in a given space. The 

 trouble does not arise when the interspaces are relatively 

 wide compared with the breadth of the lines, but it does 

 so when the breadth of the interspaces approaches that of 

 the lines. It is the black and white dot image that is 



