APEIL 24, 1903.] 



SCIENCE. 



675 



geodetic work * and. the pendulum are among 

 the first applications to find recognition, but 

 the expectation of M. Guillaume is that it 

 will prove possible to adapt other nickel-steel 

 alloys for substitution for the filament of-the 

 common ' incandescent ' lamp, a work in fact 

 already in progress. 



M. L. Dumas, in his ' Les aciers au nickel 

 a haute teneur ' f describes the mechanical 

 properties of above one hundred and fifty of 

 the alloys of these metals. At least one Paris 

 firm, Eadiguet et Massiot, on the rue Chateau- 

 d'eau, has undertaken the marketing of these 

 alloys. 



These new discoveries and their outcome 

 may not have as impressive aspects as those 

 which have given us nickel-steel armor-plate 

 or gun-barrels; they perhaps have more real 

 importance to the world. The supply of 

 nickel ores seems likely to prove ample for 

 the immediate future, at least, and scientific 

 men and engineers will be hopeful of still 

 other and useful products in this field. 

 Meantime, M. Guillaume deserves great credit 

 and large returns for his part in the work of 

 exploitation. E. H. Thueston. 



RADIUM. 



SiE William Crooks has written to the 

 London Times the following letter: 



In the presence of a mystery like that of 

 radium any reasonable attempt at explanation 

 will be welcome, so I will ask your permission 

 to revive a hypothesis I ventured to submit to 

 the British Association in my presidential 

 address in 1898. Speaking of the radio-active 

 bodies then just discovered by M. and Mme. 

 Curie, I drew attention to the large amount 

 of energy locked up in the-molecular motions 

 of quiescent air at ordinary pressure and tem- 

 perature, which, according to some calcula- 

 tions by Dr. Johnstone Stoney, amounts to 

 about 140,000 foot pounds in each cubic yard 

 of air; and I conjectured that radio-active 

 bodies of high atomic weight might draw 

 upon this store of energy in somewhat the 



* The recent measurement of the meridional arc 

 on Spitzbergen was effected with this alloy in the 

 measuring wires. 



t Published by Dimod, Paris, 1900. 



same manner as Maxwell imagined when ho 

 invented his celebrated ' demons ' to explain a 

 similar problem. I said it was not difiicult 

 so to modify this hypothesis as to reduce it 

 to the level of an inflexible law, and thus 

 bring it within the ken of a philosopher in 

 search of a new tool. I suggested that the 

 atomic structure of radio-active bodies was 

 such as to enable them to throw ofE the slow- 

 moving molecules of the air with little ex- 

 change of energy, while the quick-moving 

 missiles would be arrested, with their energy 

 reduced and that of the target correspondingly 

 increased. (A similar sifting of the swift- 

 moving molecules is common enough, and is 

 effected by liquids whenever they evaporate 

 into free air.) The energy thus gained by 

 the radio-active body would raise its tempera- 

 ture, while the surrounding air would get 

 cooler. I suggested that the energy thus gained 

 by the radio-active body was employed partly 

 in dissociating some of the gaseous molecules 

 (or in inducing some other condition which 

 would have the effect of rendering the neigh- 

 boring air a conductor of electricity) and 

 partly in originating undulations through the 

 ether, which, as they take their rise in phe- 

 nomena so disconnected as the impacts of 

 molecules, must furnish a large contingent of 

 Stokesian pulses of short wave-length. The 

 shortness in the case of these waves appears 

 to approach, without attaining, the extreme 

 shortness of ordinary Ebntgen rays. 



Although the fact of emission of heat by 

 radium is in itself sufficiently remarkable, this 

 heat is probably only a small portion of the 

 energy radium is constantly sending into space. 

 It is at the same time hurling off material 

 particles which reveal their impact on a screen 

 by luminous scintillations. Stop these by a 

 glass or mica screen and torrents of Eontgen 

 rays still pour out from a few milligrams of 

 radium salt, in quantity to exhibit to a com- 

 pany all the phenomena of Eontgen rays, and 

 with energy enough to produce a nasty blister 

 on the flesh, if kept n^ar it for an hour. 



In conclusion, if it is not too much tres- 

 passing on your space, I should like to express 

 the great admiration which I have,- in com- 



