90 



NATURE 



[November 22, 1900 



In ^^ Journal of the College of Science, Imperial University 

 of Tokio, Prof. H. Nagaoka and Mr. K. Honda discuss the 

 changes of volume and of length in iron, steel and nickel ovoids 

 by magnetisation, and a separate paper by Mr. K. Honda deals 

 with the combined effect of longitudinal and circular magnetisa- 

 tion on the dimensions of tubes of these metals. Among 

 various results of the combined investigation we notice that : — 

 (i) the transient current, as well as the longitudinal magnetisa- 

 tion produced, by twisting an iron or steel wire is opposite to 

 that produced by twisting one of nickel up to moderate fields ; 

 (2) the transient current, as well as the longitudinal magnetisa- 

 tion produced, by twisting an iron, steel or nickel wire reaches 

 a maximum in low fields ; (3) in strong fields the direction of 

 the current, as well as the longitudinal magnetisation, is the 

 same in iron, steel and nickel. In alluding to this work we 

 cannot but draw attention to the evidence of Japanese enter- 

 prise that is afforded by the publication of a journal containing 

 scientific papers in English and German by Japanese professors 

 and university graduates. 



In the Philosophical Magazine for September Dr. Sydney 

 Young discusses the Law of Cailletet and Mathias, according to 

 which the mean of the densities of a liquid and its saturated 

 vapour for any stable substance is a rectilinear function of the 

 temperature. It appears, among other results of this investi- 

 gation, that the law, thou;Th approximately satisfied, is not 

 absolutely true unless the ratio of the actual to the theoretical 

 density at the critical point has the normal value 377. In most 

 cases if the mean density be expanded in powers of the temper- 

 ature, the sign of the coefficient of the second power depends on 

 whether the ratio in question is greater or less than the normal. 

 The coefficient of the second power is so small that the linear 

 formula may be used to calculate the critical density from 

 observations at temperatures above the boiling point, but the 

 error thus introduced becomes considerable if it be required to 

 calculate the critical density from observations of mean densities 

 at lower temperatures ; moreover, as pointed out by Guye, the 

 law fails when the molecules differ in complexity in the liquid 

 and gaseous states. 



In the Journal de Physique for September, M. E. Mathias 

 discusses two interesting groups of loci relating to the thermo- 

 dynamic properties of a liquid in presence with its saturated 

 vapour. The first is the locus in the {p,v) plane of points, such 

 that the volume of the liquid is equal to that of the vapour (the 

 total mass being unity). This locus, the author finds, is a 

 curve constantly convex towards the axis of abscissae, and is 

 the only one of the curves defined by the constancy of the ratio 

 of the volumes of the liquid and vapour, which cuts the curve of 

 saturation at a finite angle at the critical point. M. Mathias 

 proves that the locus has no point of inflexion, but that the 

 angular coefficient increases with the temperature. The second 

 group discussed consists of the curves for which the masses of 

 the liquid and vapour are constant. In accordance with Raveau's 

 investigation, the only one of these curves which cuts the curve 

 of saturation at a finite angle is that corresponding to equal 

 masses of liquid and vapour. 



Mr. S. H. Burbury communicates to Wiedemann's Annalen 

 a reply to certain objections raised by Herr Zemplen Gyozo 

 against his modifications of the Kinetic Theory of Gases. In it 

 he gives certain amplifications of his proof of the property that 

 the mean values of the products of velocities of neighbouring 

 molecules of a gas are positive, and discusses the point at which 

 his method diverges from those leading to the ordinary Boltz- 

 mann-Maxwell distribution. 



. I The U.S. Department of Agriculture has issued a bulletin 

 containing records of investigations made by Mr. M. E. Jaffa, 



NO. 162 1, VOL. 63] 



at the Agricultural Experiment Station of the University of 

 California. A number of analyses of food materials were made, 

 and dietary studies were conducted with a football team and 

 with a chemist's family, as well as with a number of infants. In 

 one instance the metabolism of nitrogen of an infant was also 

 studied. Such investigations cannot fail to furnish aid in fixing 

 upon dietary standards, and the proper factors to be used in 

 computing the amounts eaten by persons of different ages as 

 compared with an adult man. 



From Messrs. B. O. Peirce and R. W. Wilson we have 

 received a paper on the thermal diffusivities of different kinds of 

 marble, published in the Proceedings of the American Academy 

 of Arts and Sciences, xxxvi. 2. The tables which the authors 

 give of the specific heats of various marbles are useful for several 

 purposes, and the law of variation of the specific heat of dry 

 Carrara marble with the temperature appears to be weU 

 represented by the formula S =oi844-(- 0*000379 fi. 



At the last meeting of the Liverpool Geological Society, a 

 paper was read on the carboniferous limestone of Anglesey, by 

 the late Mr. G. H. Morton, The paper was left by the author 

 in a finished state, and was intended by him to be the concluding 

 portion of the series of papers on the carboniferous limestone of 

 North Wales, on which he had been engaged for a period of 

 nearly foriy years. We are informed that, in addition to the 

 paper itself, Mr. Morton left revised lists of fossils brought up 

 to date with their comparative rarity or otherwise, for the dis- 

 tricts previously described, but unfortunately the list for Anglesey 

 was not completed, as he intended to visit one or two localities this 

 summer to check his lists. It is intended to print the completed 

 lists, but not the Anglesey list. Lists for certain localities in 

 Anglesey were incorporated by Mr. Morton with his paper, 

 which will be printed in full in the Society's Proceedings. 



A LECTURE on the coal resources of Victoria, Australia, was 

 delivered at the Imperial Institute, on Monday evening, by Mr. 

 James Stirling, mining representative [of the Colony. The 

 attention of most nations is now turned to their coals. The 

 demand to-day, owing to the rapid development of industries 

 and extension of commerce, is greater than it has ever been 

 before. The Australian Colonies have large areas of coal-bear- 

 ing territory, and up to the present have produced a million tons 

 of coal, the largest output having been from New South Wales. 

 After giving a short account of the first discovery of coal in 

 Victoria, Mr. Stirling said that about ten years ago he had been 

 deputed to investigate the Gippsland coalfields, and he had been 

 able to prove that within an area of 3,000 square miles of Jurassic 

 rocks there were a number of seams of good black coal from 2 

 to 5 feet in thickness. But it is in brown coal that Victoria is 

 specially rich. From borings carried on over a distance of 50 

 miles in the Latrobe Valley, Mr. Stirling has estimated that 

 there cannot be less than 31,144,400,000 tons of brown coal. 

 In several places shafts had been sunk through beds of from 

 20 to 200 feet thick, and at one place a coal bed, 70 feet 

 thick, is being worked as a quarry by open face. Various 

 analyses of these coals have shown them to be superior to the 

 average German brown coal, and to have a much smaller per- 

 centage of ash. Austria, Germany and Italy have put their 

 smaller deposits of this coal to commercial uses by compressing 

 it into briquettes, distilling oils, etc., and the same could be 

 done in Victoria, besides converting the fuel directly into 

 electrical energy. 



The Geological Survey has published the second part of *' The 

 Geology of the South Wales Coal-field," in which the country 

 around Abergavenny, included in the new series map, No. 232, 

 is described by Messrs. A. Strahan and W. Gibson. A study of 



