November 30, 191 1] 



NATURE 



155 



. lie at light angles to its surfaces. The canal rays are 

 received on a plate which is connected to a galvanometer. 

 'A'hen a magnetic field parallel to the axis of the tube is 



ablished, the " magnetic rays " produced fall on a 

 - cond plate, which can also be connected to the galvano- 

 meter. This plate is found to receive no current whatever 

 im the magnetic field, but the first plate receives a 



Mtive current, which decreases as the magnetic field 



reases. 



I.v laboratories remote from large towns, the absence of 



,-. gas supply is the cause of much difficulty ; and this 



:.i)plies to chemical, physical, bacteriological, agricultural, 



i metallurgical laboratory work. Carburetted water gas 



^- been used in some cases, but has been shown to be 

 .iit-Mided with some drawbacks. We have received a 

 11 iinphlet from Messrs. Mansfield and Sons, of Birkenhead, 



-iribing their oil-gas apparatus for laboratories. For the 

 ^ I- plant great durability and simplicity is claimed. Any 

 Ivind of oil (mineral, animal, or vegetable) can be used for 



acking, and no skilled labour is necessary, since putting 

 shovelful of coal on the fire every twenty or thirty 

 i.iiautes, and seeing that the oil is flowing in, is all the 

 attendance required. The oil gas produced is permanent, 

 l.as a very high calorific value, and requires no purification 

 before use. This gas can be used in ordinary burners and j 

 rq>pliances for laboratory use, provided that the gas jet is 

 I'duced in size to correspond with the higher carbon con- 

 f nts of the gas. Particulars are given in the same list of 

 Hansen burners, furnaces, drying and sterilising ovens, 

 blow-pipes, and water heaters modified to burn oil gas. 



The memorandum of the Manchester Steam Users' 

 Association for the year 1910 contains some interesting 

 investigations by their chief engineer, Mr. C. E. 

 SLromeyer, on the trustworthiness of Aiild steel. Some of 

 the results have been presented at the Iron and Steel 

 Institute ; and in the present paper Mr. Stromeyer gives 

 subsequent data confirming the view that the presence of 

 nitrogen gives a bad steel likely to crack in undergoing 

 the necessary workshop processes or in subsequent working 

 of the boiler of which it forms a part. The evidence 

 points to the fact that steels in which the percentage of 

 phosphorus added to five times the percentage of nitrogen 

 exceeds 008 will be untrustworthy in working. The 

 author has tried many mechanical tests with the view of 

 discovering one which would differentiate between trust- 

 worthv and untrustworthy steels, but without success. 

 " vcept as regards bad heat treatment, chemical determina- 

 ns, more particularly of phosphorus and nitrogen, are 

 the only available guides when the process of manufacture 

 and the composition of the raw material are not known. 

 Engineers, however, are not likely to place overmuch con- 

 fidence in a test which they cannot check, and will prefer 

 ' continue to rely on the reputations of the manufacturers, 

 nbini'd with a few mechanical tests. 



! HE third part of the work known as " Harmsworth 

 i opular Science," edited by Mr. .Arthur Mee, which is 

 appearing in fortnightly sevenpenny volumes, has been 

 received. In it the story of the evolution of the earth as 

 the abode of plant and mineral life, the appearance of 

 "an and his gradual development, and his subsequent 



iquest of nature and the organisation of human society, 

 IS continued in the same popular manner as in previous 

 issues. The work is profusely and excellently illustrated, 

 and the account it provides of the triumphs of science will 

 serve to encouiage among ordinary readers an appreciation 

 of the extent to which human progress is indebted to tho 

 1 iliours of men of science. 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences for Decembkr : — 

 Dec. 3. igh. 39m. Saturn in conjunction wiih the Moon 

 (Saturn 4° 5' S.). 

 4. I5h. 55m. Mars in conjunction with the Moon (Mars 

 o°5o'S.). 



6. 22h. cm. Mercury in conjunction with Lambda 



Sagiitarii (Mercury 0° i' S.)- 



7. 7h. cm. Mercury at greatest elongation E. of the 



Sun. 

 10. 23h. cm. Vesta in conjunction with the Moon 

 (Vesta 0° 28' S. ). 



15. I5h. cm. Mercury stationary. 



16. 2h. 58m. Venus in conjunction with the Moon 



(Venus 3" ^9' N.). 

 22. loh 54m. Sun enters sign of Capricorn. Solstice. 

 ,, I4h. 43m. Uranus in conjunction with the Moon 



(Uranus 4° 36' N.). 

 25. 4h. om. Mercury in inferior conjunction with the 



Sun. 

 29. 9h. cm. Mars stationary. 

 31. 3h. 59m. Saturn in conjunction with the Moon 



(Saturn 4° i' S.). 

 ,, 20h. loni. Mars in conjunction with the Moon (Mars 



o" I'S.). 



Observations of Mars. — Nos. 4537-8 of the Astro- 

 noinische Nachrichten contain several important records of 

 recent observations of Mars. Under date November 21 

 Prof. Lowell telegraphs : " First morning frost Mars 

 observed since November 3, 30° from S. pole on sunrise 

 limb." 



M. Antoniadi reports an encroachment of Syrtis Major, 

 since 1909, on the W.S.W. of Libya to the extent of about 

 100 km., and several other changes. The chief interest of 

 the observations appears to be in the apparent variations 

 wrought by changes in the Martian atmosphere. M. 

 Antoniadi suggests that, with these eliminated, the actual 

 changes in the majority of the small details of the planet's 

 surface would be very few. The intrinsic colour of such 

 " ties " as Argyre i, Noachis and Hellas, it is deduced, is 

 red, and their apparent bronze hues are produced by the 

 passage of yellow cloud screens. 



M. Comas Sola records observations made at the Fabra 

 Observatory, Barcelona, during October 9-16. A new 

 canal was seen on October 9 to the east of Syrtis Major ; 

 it appeared to correspond to a prolongation of Nubis, 

 which, passing L. Moeris, extended as an arc towards 

 Triton. The whole region of Isis and Libya was covered 

 by an immen.se, oval, brilliant cloud on October 11, the 

 new canal being completely hidden in parts ; this veil 

 afterwards moved away at about 30 km. per hour. M. 

 Comas Sola tentatively suggests that volcanic action on 

 Mars would account for the production of these massive 

 veiling clouds. 



Important changes are also reported by the Jarry- 

 Desloges observatories at Massegros and Sdtif. Nepenthes 

 and Nilosyrtis are said to be enormous, and Ausonia and 

 Hesperia greatly changed ; early in November the diameter 

 of the south polar spot was 1-2''. 



Are the White Nebulae Galaxies? — This question is 

 attacked from several directions by Prof. F. W. Very in 

 No. 4536 of the Astronomische Nachrichten, and the dis- 

 cussion of the various points is exceedingly interesting. 

 Considering the relative brightness of nebulae of different 

 diameters, he arrives, first, at the conclusion that the 

 light from these extra-galactic bodies does suffer absorp- 

 tion in interstellar space, and therefore one of the great 

 objections to an infinitely extended universe, the apparent 

 darkness of the sky, is explained. Then the apparent sizes 

 and brightnesses of these bodies are compared with those of 

 other celestial bodies of which the distances are approxi- 

 mately known. This leads to results as to the intrinsic 

 brightness of the white nebulae, hence to the question of 

 their star-density, and, finally, it is found that these celes- 

 tial objects are probably galaxies. Their diameters appear 

 to differ to at least a fourfold extent, and the dimensions 

 and brightness of the component stars are closely allied to 

 those obtaining in our own stellar system. Of course many 

 assumptions are necessary in such a discussion ; but it is 



NO. 2196, VOL. 88] 



