December 4, 1902] 



A A TURE 



IO' 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 



• pressed by his correspondents. Neither can he undertake 



to return, or to correspond with the writers of, rejected 



manuscripts intended for this or any other part of Nature. 



No notice is taken of anonymous communications. ] 



Becquerel Rays and Radio-activity. 



In your report of the meeting of the Physical Society of 

 October 31, I find the following sentence given as having been 

 said by me in the course of some remarks on Mr. Ridout's 

 paper on the size of atoms, with the four words which I under- 

 line accidentally omitted. 



" If the electrions, or atoms of electricity, succeeded in getting 

 out of the atoms of matter, they proceeded with velocities which 

 might exceed the velocity of light, and the body was radio- 

 active." 



The omission of those four words made it appear that I had 

 considered the velocity of the escaping electrions to be essentially 

 the velocity of light. In reality, the electrions may escape with 

 velocities possibly less or possibly more than the velocity of 

 light, but certainly not all with one definite velocity. 



It is probable that the electrification of air produced by the 

 breaking up of liquids into drops, 1 by a jet of water falling 

 through air, 2 by water-falls, 3 by the bubbling of air through 

 water and other liquids, and by the shaking up of liquids and 

 gases in a bottle, 4 are all to be explained by the splashing out 

 of electrions in consequence of violent vibrations of molecules of 

 the liquid at surfaces of separation between liquid and gas in 

 rapid relative motion, and at places of disruption between two 

 portions of liquid. Kelvin. 



Netherhall, Largs, Ayrshire, November 27. 



[The official report of Lord Kelvin's remarks was printed as 

 received. — Editor.] 



The Conservation of Mass. 



With reference to the letter from Mr. Sommerville in your 

 present issue, may I state that, in the discussion at the Belfast 

 Meeting of the British Association, I pointed out that the height 

 in the scale pan at which a thing is weighed affects its apparent 

 weight and that the change from this cause is quite within the 

 capacity of the best balances? I also referred to the last report 

 from Sevres by Dr. Guillaume, who made the interesting state- 

 ment that it would be certainly possible now to observe that one 

 pair of kilogram weights side by side weighed more than they 

 would do when resting one on the other. 6 



These small differences due to distance from the centre of 

 the earth are, however, considerably smaller than the discrep- 

 ancies obtained by Dr. Landolt, but I mentioned them as repre- 

 senting the kind of unexpected disturbance that might come in 

 without discovery. C. V. Boys. 



Germs in Space. 



I have received the enclosed letter from Mexico with a 

 request to forward it to you ; and accordingly I do so, since I 

 suppose it not impossible that the dust of space might contain 

 life germs of some kind. I do not think the suggested bom- 

 bardment by electric corpuscles sufficient cause, though electric 

 repulsion might sometimes act, and it has been suspected that 

 the earth may have a faint cometary tail ; but no such action is 

 needed to account for the existence of cosmic dust of any kind. 



Whether the advent of new diseases could be thus accounted 

 for is a possible matter for debate ; and incidentally it has struck 

 me to ask whether there can possibly be any physiological 

 discrimination between the, so to speak, windward and leeward 

 sides of the earth on its journey through the ether, giving the 

 morning hours a different "feel" from the afternoon hours. 

 The idea, I admit, is extremely improbable. Oliver Lodge. 



The University, Birmingham, November 19. 



> Holmgren, Swedish Academy of Sciences, 1873. 

 2 Maclean and Goto, Phil. Mag., August, 1890. 

 ;; Lenard, Ann. dt-r Phys. und Chem., 1892. 

 ' K.:lvin,^ Maclean and Gait, R.S. Proc. and Trans., 1895. 

 5 " La Convention du Metre et le Bureau International des Poids et 

 Mesures," p. 145 (1902). 



NO. 1727, VOL. 67] 



It is commonly assumed (cf. e.g. Nature of October 16, 

 p. 602) that if life did not originate upon the earth, it must have 

 come upon a meteorite. How it got on the meteorite is not 

 explained. 



It occurs to me that there is no reason why small living bodies 

 (e.g spores of bacteria) should not be floating about by them- 

 selves in space. We know from recent experiments that the 

 cold of space would not in the least destroy their germinating 

 power, but, on the contrary, would (I presume) preserve them in 

 a dormant state indefinitely. 



Now, why should not such bodies gradually settle down upon 

 the earth, without any destructive friction? If this can be, the 

 meteor hypothesis becomes wholly unnecessary. [It is the same 

 hypothesis : only the meteors assumed are extra small. — O. L.] 



We still have to account for the living bodies in space. Is 

 there any way in which minute particles (as bacterial spores) 

 could leave the earth (or any other planet)? They could be 

 carried far up in atmospheric currents, and my friend 

 Mr. Weinztrl has found bacteria in the mountain air of the arid 

 parts of this country. Is it possible that electric currents (such 

 as produce the aurora) could in some cases carry them far 

 enough to permit them to escape into space ? I do not know 

 enough about electricity to judge of this possibility. 



Theo. D. A. Cockerell. 



East Las Vegas, New Mexico, U.S.A., November 2. 



The Leonid and Bielid Meteor-showers of 

 November, 1902. 



In a letter just now received from Mr. W. H. Milligan, in 

 Belfast, some interesting details are given of observations made 

 in his watch for Leonids at and near the November date of the 

 shower's recently looked for reappearance. As a cloudy state 

 of the sky prevailed generally in England on the nights in 

 question, the result obtained in a prolonged clear view of the 

 sky on at least one of the two most probably predicted mornings 

 of November 15 and 16 for the shower's reappearance, that but 

 one true Leonid, and no sign whatever of any great abundance 

 of the shower, was visible in a watch of 4 hours on the first of 

 those two mornings, possesses considerable interest from the 

 fresh support which it affords to the lately calculated conclusions 

 of very eminent astronomers, that the meteor-stream's celestial 

 route, instead of just crossing the earth's orbit-track, as it did in 

 the shower's three last previous returns and in many bygone 

 centuries, now probably falls, by the effects of planetary per- 

 turbations on its course, sufficiently far inside the earth's orbit 

 to no longer give us the magnificent spectacle of a great star- 

 shower. 



On the mornings of November 15 and 17, only (on the last of 

 which the sky was overcast in Belfast), could short and tolerably 

 clear views be here obtained of the brightly moonlit sky ; and 

 that the shower was indeed feebly active on the former morning 

 was shown by one small true Leonid's appearance at 15(1. 52m., 

 of second magnitude, shooting overhead from 134° + 47*2° to I26J 3 

 + 54°, about 8° in gths of a second, as from a radiant point at 

 151" + 21°, the only" meteor seen in a brief half-hour of cloudless 

 sky well watched for the Leonids from 3h. 45m. to 4h. 15m. 

 a.m. On the night of November 16-17, no meteor at all was 

 visible in a full hour's watch in clear sky from Ilh. 45m. to 

 I2h. 45m. From Mr. A. King, at Leicester, I have just now 

 heard that he observed one meteor only — a Leonid— in a 25m. 

 watch on the latter night, and that in ii hours on the early morn- 

 ing of November 13 (the only other cloudless time at Leicester 

 in that November period), he observed 7 meteors, not one of 

 which was a Leonid. 



The watch, this year, for Bielid meteors on November 23-24 

 was about equally unproductive of both periodical and ordinary 

 meteors ; for in a watch of 4 hours' duration, from 7h. to r ih. on 

 the first of those two nights (the next night being cloudy), Mr. 

 Milligan reports from Belfast that no Andromede at all was 

 there observed, and in 2\ hours of clear sky, until midnight, here, 

 only two shooting-stars '(both in the first hour, and none in the 

 last li hour of the watch) were seen, neither of which were 

 Andromede or Bielid meteors. In ii hour on the second night, 

 until moonrise and cloud and rain interfered at 1 5h. , only one true 

 Bielid meteor and two other shooting-stars were here recorded. 



Regarding his long watches at Belfast for the Leonids, in 

 their recent period, Mr. Milligan writes thus :— 



" Below I give a record of the watches kept. Although the 

 results are few, yet from the fact of having seen three meteors — 



