448 



NATURE 



[March 9, 1905 



must mean the loss of the last lot of ballast, and repeated 

 expansions must result in the loss of so much gas that 

 the balloon sinks eventually to earth. The latest plan pro- 

 posed to overcome this weakness is described at length in 

 the article. Steam circulating in a long aluminium worm 

 will be used to heat the gas of the balloon, and contraction 

 will mean merely the condensation of so much steam into 

 water, while expansion will be brought about by its recon- 

 version into steam. The difficulty consists in preventing 

 any loss of water, and M. Santos-Dumont explains how he 

 proposes to effect this. The successful use, at an early 

 date, of air-ships in Arctic exploration is predicted, anc' 

 the part that air-ships will take in the warfare of thf 

 future is outlined. 



We have received from Messrs. A. Gallenkamp and Co. 

 specimens of some new spectrum tubes which we have 

 tested with very satisfactory results. The tubes, three in 

 number, contained argon, helium, and a mixture of argon 

 and helium, and the trial showed that they are a great 

 advance on any other forms that have previously been ex- 

 amined. For spectroscopic work they should be of the 

 greatest service, for the exceeding brilliancy of the gases, 

 when only a small coil, with or without a jar in circuit, is 

 used, will render them particularly useful in research work. 

 The tubes themselves are of rather novel construction, the 

 main point being the insertion of a short capillary tube in 

 a tube of larger dimensions, the latter being connected 

 with two other tubes fixed at right angles, and containing 

 the electrodes. The current passing from one electrode to 

 the other has to pass through the capillary, and the gas 

 in this space is rendered very brilliant. When placed end on 

 to the slit of a spectroscope, the bulb end of the tube con- 

 taining the capillary being on the slit side, a method first 

 adopted by Monkhoven to obtain the maximum of brilliancy 

 of the illuminated gas on the slit, the result is a brilliant 

 concentration of light which can be examined with large 

 dispersion. The tubes are strong, compact, and well made, 

 and can be strongly recommended both for student and 

 research use. 



Prof. A. H. R. Blller, writing irom the University of 

 Manitoba, describes some striking electrical effects due to 

 the dryness of the atmosphere at Winnipeg. The air 

 during the winter months contains so little water-vapour 

 that bodies charged with electricity lose their charges re- 

 latively slowly. When the thermometer is low, ranging as 

 it often does for a week or more at a time from o° to 

 — 40° F., very little friction, such, for instance, as may 

 be produced by walking along a carpet, causes a person 

 to become charged with sufficient electricity to produce a 

 visible and audible spark on touching an iron bedpost, the 

 radiator, the gas-tap, or any other conductor. It is a 

 favourite amusement of some children to take sparks from 

 each other's noses after running about a carpeted room. In 

 the Manitoba Hotel, now burnt down, there was a ball- 

 room w-ith some iron pillars in it. Prof. Buller was told 

 by a trustworthy eye-witness that after a dance dancers on 

 several occasions have been " severely stung " by accident- 

 ally coming into contact with one of the pillars. Many ladies 

 have considerable difficulty in combing their hair ; for during 

 the process it becomes so charged with electricity that it 

 stands out in the most astonishing manner. Even the short 

 hair of a man, when being combed, often "crackles," 

 " stands on end," arid in the dark produces a display of 

 sparks. It is quite easy to light the gas with a spark 

 from the finger when matches are not handy by merely 

 shuffling a few paces over the carpet and then holding a 

 finger to the burner. On February 6, at i p.m., when a 

 NO. 1845, VOL. 7 



thermometer in the shade out of doors registered —5° F. 

 and indoors 62° F., Prof. Buller found that a spark half 

 an inch long could be obtained between his finger and an 

 earth-connected iron pipe after sliding his feet smartly for 

 twenty paces along the maple-wood floor of his laboratory. 

 In the chemical laboratorv calcium chloride mav be ex- 

 posed to the air for some weeks without showing the least 

 apparent signs of deliquescence. In order to demonstrate 

 the deliquescence of this substance to the stud»nts, the pro- 

 fessor of chemistry is obliged to use a damp-chamber. 



No. 2 of vol. ii. of he Radium contains an account by 

 M. J. Danne of the deposits of pyromorphite containing 

 radium which have recently been discovered at Issy-l'Ev^que 

 (Saone et Loire), and the first part of a study of phosphor- 

 escence by M. L. Matout. A description is also given by 

 Dr. Robert Abbe, of St. Luke's Hospital, New York, of 

 several cures of external tumours and cancerous growths 

 which were effected by means of radium. 



An investigation of the effect of temperature on the 

 magnetisation of steel, nickel and cobalt by Prof. H. Nagaoka 

 and S. Kusakabe constitutes article g of vol. xix. of the 

 Journal of Science of the University of Tokio. The most 

 interesting results were obtained with cobalt and with 

 tungsten-steel. The former is characterised by undergoing 

 several remarkable changes of magnetisation as the 

 temperature is raised, whilst with tungsten-steel, between the 

 temperature of disappearance of magnetism on heating and 

 that of its reappearance on cooling, there exist at least five 

 corrugations in the curve of magnetisation in a constant 

 field. When once the magnetisation has disappeared it 

 cannot be recovered until the temperature has been lowered 

 by about 240° C, and the cooling curve again exhibits 

 peculiar sinuosities. In addition to these peculiarities, 

 tungsten-steel shows a very pronounced recalescence at 

 660° C, this temperature practically coinciding with that 

 at which magnetism reappears in the cooling metal. 



In No. 3 of vol. vi. of the Physikalische Zcilschrift 

 Messrs. Elster and Geitel describe further investigations of 

 the highly radio-active muds from the thermal springs of 

 Nauheim and Baden. These sediments are completely 

 soluble in hydrochloric acid, and on adding dilute sulphuric 

 acid to the solution, a precipitate of radio-barium sulphate is 

 obtained having an activity many times as great as that of 

 an equal quantity of the original mud. The oxides pre- 

 cipitated by ammonia from the filtrate of the barium 

 sulphate are also radio-active, the character of the emana- 

 tion indicating the presence of thorium, although this sub- 

 stance could not be separated by chemical methods. Prof. 

 G. Vicentini and M. Levi de Zara, in the Atti of the 

 Royal Venetian Institute (vol. Ixiv., ii., 95), also deal with 

 the question of radio-active sediments. The radio-activity 

 of the mud and of the incrustation formed by the thermal 

 springs of Battaglia, .Abano, Montegrotto and the Lake of 

 Lispida has been measured. The Cittadella spring at Monte- 

 grotto is particularly noteworthy on account of the high 

 value of its radio-activity and of the fact that this appears 

 to be due to radium only. The air in the vicinity of the 

 springs was in all cases found to contain notable quantities 

 of a radio-active emanation. 



The latest addition to the Philosophische Bibliothek pub- 

 lished by the Diirr'schen Buchhandlung, Leipzig, is a 

 translation of Spinoza's " Ethics," with an introduction and 

 notes, by Dr. Otto Baensch. The volume is No. 92 of the 

 series of philosophical manuals in which it is published, 

 and its price is three marks. 



