December 5, 1912] 



NATURE 



401 



peratures up to 1500° C. This furnace was designed 

 with a view to investigate, at temperatures up to 

 1500° C, certain cases of heterogeneous equilibrium 

 in which the equilibrium is defined by the pressure of 

 the system. Instances are the dissociation of oxides, 

 nitrides, and carbonates and the reduction of oxides 

 by carbon. — R. E. Slade and F. D. Farrow : .An inves- 

 tigation of the dissociation pressures and melting 

 points of the system copper — cuprous oxide. The 

 melting point (temperature, composition) diagram of 

 the system copper — cuprous oxide has been con- 

 structed. The following are the principal points : — 

 Melting point of copper 1083°. Eutectic Cu,0 3'5 per 

 cent., Cu g6'5 per cent., 1005° (determined by Heyn). 

 Two liquid phases appear at 1195°, the denser one 

 having the composition Cu„0 20 per cent., Cu 80 per 

 cent., and the lighter one Cu,0 95 per cent., Cu 5 per 

 cent. Melting point of cuprous o.xide 1210°. The 

 critical temperature at w-hich the two liquid systems 

 become identical is too high to be determined. — Dr. A. 

 Russell : Note on the electric capacity cocfllcients of 

 spheres. In connection with Mr. Jeffery's paper pub- 

 lished in vol. Ixxxvii. of the Proceedings, p. 109, the 

 author gives and refers to formulas by means of which 

 the values of the capacity coefficients of equal spheres 

 c.nn be easily found. He uses these formulcE to check 

 the tables given in Mr. Jetfery's paper. — W. J. 

 Harrison : The motion of viscous liquid due to uniform 

 and periodic motion maintained over a segment of an 

 infinite plane boundary. — Prof. B. Hopklnson and G. 

 Trevor- Williams : The elastic hysteresis of steel. A bar 

 of steel, the reduced portion of which is 4 in. long by 

 5 in. diameter, is subjected to alternating stress in the 

 high-speed fatigue-testing machine described in a pre- 

 vious communication. This machine gives direct axial 

 stress up to range of 30 tons per square inch or more, 

 between equal limits of tension and compression, at a 

 rate of about 120 cycles per second. The elastic 

 hysteresis is measured by determining, with the aid 

 of thermo-couples, the fall of temperature between the 

 centre of the piece and each end when it is undergoing 

 alternating stress within the elastic range. The dissi- 

 pation of energy corresponding to a given fall of 

 temperature is determined by heating the specimen 

 with an electric current and measuring the watts 

 dissipated by resistance. In the mild steel used in 

 the experiments the energy dissipated per cycle when 

 the limits of stress are +12A tons per square inch 

 (giving a range of 25 tons, which is within the limit- 

 ing elastic range as determined by ordinary fatigue 

 experiments) is about 25,000 ergs per c.c, and gives 

 a fall of temperature of about 5°. This is of the same 

 order of magnitude as that due to the magnetic 

 hysteresis in similar material under strong magnetic 

 forces. The elastic hysteresis varies appro.ximately as 

 the fourth power of the stress range. — W. R. Bous- 

 field : Ionic size in relation to molecular physics, to- 

 gether with a new law relating to the heats of forma- 

 tion of solid, liquid, and ionic molecules. In a former 

 paper it was shown that ionic volumes (derived from 

 mobilities) and solution volumes were connected by an 

 empirical linear relation. 



EV, = «-^I„. 



In the present paper a new empirical relation is estab- 

 lished of the form 



D-'=;>-jfX(I„-K). 

 where D is the effective molecular freezing point de- 

 pression, i.e. A/N(i + a). In the former paper the 

 experimental data were given for KCl and NaCI, and 

 in the present paper for LiCI, which data determine 

 the constants a, b, p, q, for each salt. It is now 

 shown that we can express in terms of these con- 

 stants — (i) The factor required to reduce arbitrary 

 NO. 2249, VOL. 90] 



ionic volume units to absolute units ; (2) the volume 

 of the ionic nuclei ; (3) the volume and mean density 

 of the "watery atmospheres" associated with the ions. 

 It is shown for a group of fourteen solid and liquid 

 salts and acids that their heats of formation are given 

 by the expression 7/85V + Hj + H„, where 5V is the 

 reduction of volume (or contraction) which takes place 

 on combination, and Hj and H„ are constants for tlie 

 elements of which they are composed. It is found that 

 the heats of ionisation of the three salts may also be 

 expressed under the same law as 



27/8SV-l-Hi + H,+ r3«-29 



where 5V includes volume change of combined water 

 as well as of ionic nuclei, n is number of molecules of 

 combined water and —29 is a constant which repre- 

 sents endothermic changes involved in ionisation. — 

 Dr. J. Emerson Reynolds : The synthesis of a silical- 

 cyanide and of a felspar. During recent years the 



j writer has obtained many compounds of silicon in 



I which that element is directly united with the nitrogen 

 oi various organic groups, and amongst these silico- 



I cyanogen, SiN, in combination. The proof so obtained 

 that silicon has a strong attraction for trivalent 



i nitrogen in organic substances suggested that a 

 similar capacity is operative in the mineral kingdom, 

 but in respect of trivalent aluminium acting in the 

 nitrogen r61e towards silicon. It seemed probable 

 that some at least of the more important rock-forming 

 minerals may be regarded as fully oxidised products of 

 a\um\no-silicides somewhat analogous to SiN. The 

 experimental. work recorded in the paper supports this 

 view, and has resulted in the formation of a remark- 

 ably stable substance termed Calcium Silicalcyanide, 

 Ca(SiAl),, analogous to ordinary calcium cyanide, 

 Ca(CN),. From this silicalcyanide a further synthesis 

 of the felspar Anorthite, CaSi„.A.LOg, has been effected. 

 — Prof. C. Niven and A. E. M.Geddes: A method of 

 finding the conductivity for heat. 



Royal Microscopical Society, November 20. — Mr. H. G. 

 Plimmer, F.R.S., president, in the chair. — E. Heron- 

 Allen and A. Earland : The distribution of Saccainmina 

 sphaerica (M. Sars) and Psammosphoera fusca 

 (Schulze) in the North Sea, with particular reference 

 to the suggested identity of the two species. These 

 Foraminifera, belonging to the family Astrorhizidje, 

 and originally described as from the North Sea, but 

 occurring also in all the great oceans, have been the 

 subject of considerable controversy. Dr. Ludwig 

 Rhiimbler asserts that Psammosphoera is only an 

 immature stage of Saccammina. .As a result of the 

 examination of about 150 dredgings made in the North 

 Sea, the authors have no hesitation in affirming that 

 the life-history of Saccammina, as recorded by 

 Rhiimbler, is a composite sketch, involving three 

 separate and generally recognised specific organisms : 

 Stages I. to III. represent the life-history of Crithio- 

 nina mamilla (A. Goes); stage IV. is Psammosphoera 

 fusca (Schulze), an extremely variable species, which 

 occurs both free and sessile, but is in all its stages 

 normally recognisable by the absence of a general 

 aperture; stages V. to VII. represent the complete 

 life-cycle of Saccammina sphaerica (.Sars), so far as 

 it is a shell-bearing organism. — Rev. Hilderic Friend : 

 British Henleas. The Henleas are microscopic anne- 

 lids belonging to the familv of Euchytraeids. The 

 genus was created in 1880 by Michaelsen. and con- 

 tained four authentic species and four which were 

 doubtful. The "resent paper gives an enumeration 

 of no fewer than nineteen species, eighteen of which 

 are found in England and one in Ireland. Of these, 

 seven new to science were found at Hastings in 

 December last, and three have been found in Notting- 

 ham during the present year. — J. Murray : African 



