36o 



NATURE 



[August 9, 1900 



due, like most other events upon the earth, to the shiftings 

 about of energy which intervene between the advent of energy 

 and from the sun and its radiation from the earth into space ; and 

 to take it into account in an investigation based on the laws of 

 the partition of energy, it would be necessary to extend that 

 partition beyond the earth to the sun and to the intervening 

 aether. 



B 3. So, again, the great absorption of solar radiation which 

 takes place in the outer layers of the earth's atmosphere will 

 have to be taken into account, and as it has not been included 

 under function tt, it still further augments the part which the 5 

 function takes inequation (i) and renders equation (2) an insuffi- 

 cient one for the purposes of the investigation. 



B 4. The commotion going on in the atmosphere consists in 

 part of electrical phenomena. Some of these — thunderstorms, 

 auroras, the electrical condition of fogs, &c. — can be observed 

 from the stations which men occupy at the bottom of the 

 atmosphere, and are of such a kind that they must be ac- 

 companied by a charged condition of that stratum of the 

 atmosphere the density of which renders it a better conductor 

 than the atmosphere above it and below. This stratum, then, 

 and the strata above it receive charges of electricity which, 

 according to the varying condition of the strata further down, 

 will sometimes be disguised electricity and at other times un- 

 disguised. This electrified condition of the upper regions, 

 co-operating with ascending currents, which necessarily increase 

 in speed as they advance, will presumably give rise to 

 prominences upon the earth's atmosphere, upon which the 

 density of the electrification will be intensified and from which 

 in consequence gaseous molecules find it easier to escape than 

 from other situations. In this and other ways electricity may 

 help the escape. 



Now of these agencies, all of which affect the rate at which 

 gas can escape from the earth, none is included in the investi- 

 gation which Mr. Cook has made of that phenomenon ; and 

 only the first (B i) is dealt with by Prof. Bryan. Moreover, it 

 is probable that these are not the only ways in which nature can 

 intervene, and which have been overlooked. The supposition 

 then that either of the probability laws made use of by those 

 investigators can be applied to our actually existing atmosphere, 

 without a large correcting function 5, would appear to be a 

 mistake ; anfl, if so, the inferences from those laws when so 

 applied are not part of a real interpretation of nature. It need 

 not therefore occasion any surprise that, in the case of helium, the 

 facts of nature seem to negative those inferences. (See Nature 

 of May 24, 1900 ; the second column of p. 78.) 



Edinburgh. 



Royal Society, July 16.— Lord Kelvin, President, in the 

 chair. — Lord Kelvin read a paper on the motion in an infinite 

 elastic solid by the motion, through the space occupied by it, of 

 a body acting on it only by attraction and repulsion. The ideal 

 atom considered in this paper was a region of space in which the 

 ether was changed in density by the action of forces upon it. In 

 the particular case chosen for development the atom was taken 

 as spherical with spherical distributions of density within it, and 

 every element of matter was supposed to act on every element of 

 the ether according to the Newtonian law. The further assump- 

 tion was made that the average density of the ether within the 

 atom was the same as if the atom were not present. The atom 

 and the ether were then supposed to be in relative motion, and 

 the total kinetic energy of the ether within the atom was calcu- 

 lated, as also the effective inertia of the ether in the space 

 occupied by the matter. On the assumption that the density 

 of the ether at the centre of the atom was loi times greater than 

 the undisturbed density, it was found that a refractivity was 

 obtained a little smaller than that of oxygen. By assuming that 

 the average density was in excess or defect of the undisturbed 

 ■density of the ether, we could extend the method so as to 

 include electrical actions.— In a second paper, on the number of 

 molecules in a cubic centimetre of gas. Lord Kelvin pointed out 

 that in the preceding paper he had been obliged to take the 

 number as 4 x 10-* instead of Maxwell's number, 19 x iqI*. — In 

 a paper on the hyperbolic quaternion, Dr. Alex. Macfarlane 

 showed how by the introduction of "real" instead of "imagi- 

 nary " vectors, quaternion theorems of spherical geometry could 

 be generalised so as to be applicable to hyperbolic geometry. — 

 Sir John Murray and Dr. Philippi communicated a preliminary 



NO. 1606, VOL. 62 1 



note on the deep-sea deposits collected during the Valdivia 

 expedition of 1898-9. Leaving Hamburg and passing round by 

 the north of Scotland, the Valdivia proceeded southwards by 

 the west coast of Africa to the Cape, thence to the Antarctic 

 seas, returning by way of the Indian Ocean and the Suez Canal. 

 Generally speaking, the nature of the deposits agreed with what 

 was already known, but fuller information was gained in many 

 instances. For example, off the mouth of the Congo samples of 

 coprolitic mud had been obtained, largely made up of little oval 

 pellets of mud which had passed through the intestines of 

 echinoderms. These had consolidated and were apparently in 

 the process of being transformed into glauconitic and phosphatic 

 concretions. The study of the formation and distribution of 

 glauconite was geologically of great importance, and a detailed 

 examination of the Valdivia collections would probably throw 

 much light on the subject. — Prof. J. C. Beattie communicated 

 a second part of his researches into the leakage of electricity 

 from charged bodies at moderate temperatures. In most of the 

 experiments described, zinc strips resting on insulated iron 

 plates were sprinkled with various salts and then heated to 

 about 350° C, the whole being enclosed in an iron box which 

 was connected to the case of the electrometer. Among the 

 substances used were common salt, alone or with iodine or 

 bromine, and similar combinations with the chlorides of lithium, 

 lead, potassium, &c. Generally a steady negative charge was 

 produced by the heating, but not always. The difference of 

 potential so obtained depended on the nature of the insulated 

 metals, but not on their distance apart. When high voltages 

 were used, the positive charge leaked away, while the negative 

 charge was retained. An explanation was offered founded on 

 Enright's and on Townsend's experiments. — A communication 

 was also presented by Dr. Thomas Muir on the theory of skew 

 determinants and pfaffians in the historical order of its develop- 

 ment up to 1857. — In a brief review of the session, the Presi- 

 dent referred to the great losses the Society had sustained 

 through the deaths of the Duke of Argyll and Sir Douglas 

 Maclagan. 



CONTENTS. PAGE 



Practical Navigation. By W. E. P 337 



The Cultivation and Production of Coffee 338 



The Birds of Surrey. By R. L 339 



Our Book Shelf:— 



Correns : " Untersuchungen ueber d. Vermehrung d. 



Laubmoose durch Brutorgane und Stecklinge " . . 339 

 Tennant : " Village Notes, and Some Other Papers " 34O 

 Letters to the Editor :— 



The Conductivity produced in Gases by the Motion of 



Negatively-charged Ions. — ^J. S. Townsend . . . 340 

 A Remarkable Hailstorm. {Illustrated.)—'^. G. 



Roberts 34i 



The Photographyof Sound-Waves and the Demon- 

 stration of the Evolutions of Reflected Wave- 

 Fronts with the Cinematograph. {Illustrated.) 



By Prof. R. W. Wood 342 



Notes 349 



Our Astronomical Column:— 



Comet Borrelly- Brooks (1900 (5) 352 



Ephemerisof Comet 1894 IV, (Swift) -352 



Variable Stars in Clusters 352 



Recent Investigations on Rust of Wheat. {Ilhis- 



trated.) By WilHam G. Smith 352 



Medicine as a Science and Medicine as an Art. By 



Dr. P. H. Pye-Smyth, F.R.S 35^ 



Mr, Balfour on Scientific Progress 358 



Societies and Academies 35^ 



