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NATURE 



\juiy 27, 1882 



The current number of the British Quarterly Re-view contains 

 an article on recent Japanese progress, which is by far the most 

 valuable that has been published on this :ubject for many years 

 past. The author, Col. H. S. Palmer, R.E., describes fully 

 the cau-es and course of the changes which have passed over the 

 "Land of the Rising Sun " in the past fourteen years; the 

 vari ius and complicated changes in the constitution and adminis- 

 tration — from the pure oligarchy which succeeded the revolution 

 of 1S68, to the system of tolerably free local government of the 

 present day — are clearly explained, and the effect of the various 

 steps in these changes made comprehensible to the general 

 reader. The writer then takes the recent reforms under various 

 heads — the army, navy, education, public works, prisons, &c — 

 and shows, by statistics, what advance has really been made. 

 The last half of the paper is, in fact, a comprehensive sum- 

 mary, with running commentary, of the Japanese government 

 statistics in every department. The knotty subject of finance is 

 treated with as much clearness as the subject admits of. Under 

 this head the almost inevitable character of the present financial 

 depression is explained ; but it is gratifying to notice that a 

 careful and impartial observer like Col. Palmer is able to con- 

 clude his article with confidence in the future of the country to 

 which he has devoted so much study. Many of the interesting 

 stati-tics in the paper have already appeared in the columns of 

 Nature. 



Dr. Holub has sent lis several papeis connected with his 

 Siu'h African explorations. There are two on the English in 

 South Africa, from the standpoint of exploration and civilisation, 

 and a similar paper on the French in Tunis ; and an interesting 

 Catalogue, with notes, of Dr. Holub's ethnographical collections. 



In connection with Egyptian troubles, Mr. Wyld haspublished 

 two maps, which may be useful to those who are watching 

 operation-. One is a plan of Alexandria and the harbour, with 

 an inset map showing the British possessions in the Old World ; 

 the other is a small map of the Isthmus of Suez and lower 

 Egypt, on the scale of twelve miles to an inch, with a similar 

 inset map. 



CONTRIBUTION OF ASTRONOMY TO THE 

 PROBLEM OF MOLECULAR PHYSICS 1 



"THE kind way in which you have received me, leads me to 

 ■*• fix, by writing, the principal points of our conversation on 

 Sunday last. I thank you heartily for offered help to realise the 

 scientific aim I have in view, and which I will now explain. 



The synthetic study of thermo-chemical phenomena, of the 

 laws of thermo-dynamics and of experiments relating to these 

 subjects of the physical sciences, has brought us to consider the 

 temperature of a body as being the mean amplitude of the 

 vibratory oscillation of molecules constituting that body. 



This definition, taken as a starting point, enables us to explain 

 and deduce all the essential laws of the mechanical theory of 

 heat. We obtain from it easily the law of Dulong and Petit, 

 that of isomorphism in systems of crystallisation, the relations 

 connecting the coefficients of expansion of all substances with 

 their atomic weight, their temperature of fusion and their 

 density, &c. 



The maximum tensions are calculated in advance with all 

 exactness, and lastly, the two great mechanical principles of heat 

 are an immediate and necessary consequence of it. 



I have, then, every reason to believe that this definition will 

 be adopted, since it satisfies as well the condition of integrability 

 of the differential equation of motion (function S of Zeuner) as 

 the definition drawn from the air or mercury thermometer 

 (definition of Regnault). 



In that case, what is the specific heat of a body ? 



The specific heat becomes the sole manifestation of the 

 attraction of molecules for one another. 



Indeed, if we multiply the space traversed (temperature) by 

 the molecular force (specific heaO, we obtain the total heat or 

 quantity of absolute work which the substance contains. 



Here, consequently, comes in an important question, wdiich is 

 by no means secondary, as has often been said — 



Is the attraction of matter for matter a fundamental essential 

 property of matter, or is it merely the result of the dynamical 

 action of the medium in which the matter exists ? 



In other terms, may one say, without its being possible to ex- 



1 A letter from M. Raoul Pictet to M. Dumas, dated Paris, December 16, 

 1881, and published in Archives des Sciences, June 15. 



plain it, Matter attracts matter without the active intermediary of 

 the medium ; or, Attraction as a. force does not exist ; it is merely 

 the manifestation of shocks of the ether which tend to approxi- 

 mate bodies according to the Newtonian law ? 



In the former case, one regards the attractive potential of 

 matter as an original capital placerl in each material element, a 

 capital which is only exhausted hy the absolute approximation of 

 all matter existing in the universe. In the latter case this poten- 

 tial is nil, and one supposes that a certain quantity of kinetic 

 energy has been communicated in the beginning of time to the 

 mass of the universe, a quantity of energy wdiich is inevitably 

 transformed under a thousand different combinations into all the 

 physico-chemical and astronomical phenomena of nature. 



In the former case \ mv- + the potential is constant. 



In the latter, | mv* alottt is constant. The solution of this 

 important question is necessary to establish physical theories in 

 a somewhat distinct manner, and to prove the intimate relation 

 exis*ing between the various elements of bodies. 



On the hypothesis that attraction is an essential property of 

 matter, we shall liken it to inertia ; thus any body will possess as 

 primordial characters, a certain quantity of inertia, without 

 which we should never come to be put in contact « ith it nor to 

 know it, and a certain quantity of attraction, wdiich will be the 

 manifestation of its proper influence on the rest of the universe. 

 Such will be the conditions of existence of matter. 



On the hypotheses that ^mv 1 alone is constant, inertia and 

 motion are the fundimental properties of matter ; shocks are the 

 means of transformation of different modes of motion. 



Let us take, then, any body and heat it. 



If we are partisans of the first hypothesis, that of potential, 

 we must expect to find simple relations between the inertia of 

 the body considered, the attraction of the molecule for one another, 

 and increase of volume of the body, the whole associated with the 

 quantity of mechanical work furnished to the body in the form 

 of heat. 



The specific hex's and latent heats will then be functions of the 

 atomic weight or inertia of the body, and the dissociation which 

 is manifested by fusion and volatilisation, will be deduced from 

 the study of the body under these two aspects, masses set in 

 motion, and potential of those masses. 



If we are partisans of the second hypothesis, supposing that 

 \ in :■■ is constant, we are obliged simply to consider the volume 

 of the body ; that is to say, the exterior surface of the smallest 

 quantity of matter. 



Indeed, shocks alone explain the phenomena. But when one 

 says shock, he says surface where the shock occurs. The greater 

 the surface the larger th; number of shocks of the ether, the 

 stronger the reaction of the matter. 



We must expect them, in this second hypothesis, to find 

 simple relations between the volumes of atoms and of molecules, 

 that is, between the co-efficients which represent the density of 

 the bodies, the number of atoms and the atomic weight, and the 

 specific heats, latent heats, and maximum tensions. 



In other terms, in the first hypothesis, molecular physics will 

 rest essentially on the atomic weight, which, by virtue of the fall 

 of bodies, represents simultaneously the idea of inertia and that 

 of attraction, essential properties ; in the second hypothesis the 

 physico-chemical phenomena are deduced mainly from the 

 volume of atoms and the medium in which the phenomena 

 occur. 



The medium becoming active, a variation of medium will 

 induce in phenomena of attraction concomitant variations quite 

 independent of matter itself. 



The spicific heats ami the latent heats may then be variable 

 elements in the same substance and at the same temperature under 

 the same pressure, according to the mechanical energy of the 

 medium in which the phenomena occur. 



Thus the whole of molecular physics is closely connected with 

 the solution of this theoretical question. 



We have sought an experimental method capable of throwing 

 some light on this problem. Without entering into too minute 

 details, we will explain the plan of this work. 



It may be accepted, I believe, that the solar system is nearly 

 independent, 'mechanically speaking, of the rest of the universe ; 

 that is to say that no motion, relatively to the centre of gravity 

 of this system, is produced in our planets by the perturbation of 

 other systems surrounding us. 



We may then call M the total mass of the solar system. This 

 mass is decomp >sed into m, m', m* . . . the respective masses 

 of the Sun, Venus, the Earth, Jupiter, &c, and 11 the mass of 



