September 5, 1912] 



NATURE 



tron i^ entirely electro-magnetic. Any such statement 

 virtually assumes a particular distribution of the 

 ekciricity in a spherical electron of given size. But 

 if electricity itself really consists of electrons, an 

 argument of this type would appear to be so penectly 

 circular that it is questionable how much weight 

 should be attached to it. If the equivalent mass of an 

 electron in motion arises slowly from the electro- 

 magnetic field produced by its motion, a neutral cor- 

 puscle of caloric should not possess mass or energy 

 of translation as a whole, though it might still possess 

 energy of vibration or rotation of its separate charges. 

 l'"or tne purpose of mental imagery we might picture 

 the electron as the free or broken end of a vortex 

 lihiment, and the neutral corpuscle as a vorte.\ ring 

 produced when the positive and negative ends are 

 united ; but a mental picture of this kind does not 

 carry us any further than the sphere coated with 

 electricity, except in so far as either image may sug- 

 gest points for experimental investigation. In our 

 ignorance of the exact mechanism of gravity it is 

 even conceivable that a particle of caloric might 

 possess mass without possessing weight, though, with 

 the possible exception of the electron, nothing of the 

 kind has yet been demonstrated. In any case it would 

 appear that the mass, if any, associated with a 

 quantity of caloric must be so small that we could not 

 hope to learn much about it by the direct use of the 

 balance. 



The fundamental property of caloric, that its total 

 quantity cannot be diminished by any known process 

 and that it is not energy but merely the vehicle or 

 carrier of energy, is most simply represented in 

 thought by imagining it to consist of some in- 

 destructible form of matter. The further property, 

 that it is always generated in any turbulent or irre- 

 versible process, appears at first sight to conflict with 

 this idea, because it is difficult to see how anything 

 indestructible can be so easily generated. When, 

 however, we speak of caloric as being generated, what 

 we really mean is that it becomes associated with a 

 material body in such a way that we can observe and 

 measure its quantity by the change of state produced. 

 The caloric may have existed previously in a form 

 in which its presence could not be detected. In the 

 light of recent discoveries we might suppose the caloric 

 generated to arise from the disintegration of the 

 atoms of matter. Xo doubt some caloric is produced 

 in this way, but those corpuscles that are so strongly 

 held as to be incapable of detection by ordinary physical 

 methods require intense shocks to dislodge them. A 

 more probable source of caloric is the Eether, which, 

 so far as we know, may consist entirely of neutral 

 corpuscles of caloric. The hypothesis of a continuous 

 ffither has led to great difliculties in the electro- 

 magnetic theory of light and in the kinetic theory of 

 gases. A molecular, or cellular-vortex, structure 

 appears to be required. According to the researches 

 of Kelvin, Fitzgerald, and Hicks, such an aether can 

 be devised to satisfy the requirements of the electro- 

 magnetic theory without requiring it to possess a 

 density many times greater than that of platinum. 

 So far as the properties of caloric are concerned, a 

 neutral pair of electrons would appear to constitute 

 the simplest type of molecule, though without more 

 exact knov ' dge of the ultimate nature of an electric 

 charge it Id be impossible to predict all its pro- 



perties. \ .i iher an sether composed of such molecules 

 would be competent to discharge satisfactorily all the 

 onerous functions expected from it, may be difficult 

 to decide, but the inquiry, in its turn, would probably 

 throw light on the ultimate structure 'f the molecule. 



Without venturing too far into the regions of meta- 

 physical speculation, or reasoning in vicious circles 

 about the nature of an electric charge, we ninv at least 



XO. 2236, VOL. go] 



assert with some degree of plausibility that material 

 bodies under ordinary conditions probably contain a 

 number of discrete physical entities, similar in kind 

 to X rays or neutral corpuscles, which are capable of 

 acting as carriers of energy, and of preserving the 

 statical equilibrium between matter and radiation at 

 any temperature in virtue of their interchanges with 

 electrons. If we go a step further and identify these 

 corpuscles with the molecules of caloric, w^e shall cer- 

 tainly come in conflict with some of the fundamental 

 dogmas of the kinetic theory, which tries to express 

 everything in terms of energy, but tlie change involved 

 is mainly one of point of view or expression. The ex- 

 perimental facts remain the same, but we describe them 

 differently. Caloric has a physical existence, instead 

 of being merely the logarithm of the probability of a 

 complex ion. In common with many experimentalists, 

 I cannot help feeling that we have everything to gain 

 by attaching a material conception to a quantity of 

 caloric as the natural measure of a quantity of heat as 

 opposed to a quantity of heat energy. In the time at 

 my disposal I could not pretend to offer you more than 

 a suggestion of a sketch, an apology for the possibility 

 of an explanation, but I hope I may have succeeded 

 in conveying the impression that a caloric theory of 

 heat is not so entirely unreasonable in the light of 

 recent experiment as we are sometimes led to imagine. 



NOTES. 



Dr. G. T. Beiluy, F.R.S., has been appointed a 

 member of the Royal Commission on Oil Fuel in suc- 

 cession to the late Dr. H. Owen Jones. 



The death is announced, at eighty years of age, ot 

 Prof. T. Gomperz, of the Universitv of Vienna, dis- 

 tinguished by his studies in philology and philosophy, 

 and well known by his work "Greek Thinkers," of 

 which an English translation appeared several ,y.c,?ns 

 ago. 



.\s previously announced, the autumn meeting of the 

 Institute of Metals will be held in London on Wednes- 

 day and Thursday, September 25 and 26. The follow- 

 ing are among the papers that are expected to be 

 submitted : — Autogenous welding by means of oxygen 

 and acetylene of copper and its principal alloys, and of 

 aluminium. Prof. F. Carnevali ; the effect of other 

 metals on the structure of the beta constituent in 

 copper-zinc alloys. Prof. H. C. H. Carpenter; the 

 effect of temperatures higher than atmospheric on 

 tensile tests of copper and its alloys. Prof. A. K. 

 Huntington; the influence of o.xygen on the proper- 

 ties of metals and alloys, E. F. Law ; the annealing 

 of coinage alloys. Dr. T. Kirke Rose ; intercrystalline 

 cohesion in metals (with an appendix on the formation 

 of twinned crystals in silver). Dr. W. Rosenhain and 

 D. Evven; oxygen in brass. Prof. T. Turner. 



We regret to announce that Prof. T. Winter, pro- 

 fessor of agriculture in University College of North 

 Wales, Bangor, died on Sunday, September i, at 

 forty-si.x years of age. Prof. Winter was educated at 

 Darlington Grammar School and Edinburgh Univer- 

 sity, where he graduated in arts. He afterwards 

 became assistant lecturer on agriculture at the Uni- 

 versity College of North Wales. Later he was ap- 

 pointed lecturer in agriculture at the University of 

 Leeds; and in 1894 he returned to the University 

 College of North Wales as head of the agricultural 

 department. He took an active part in agricultural 



