168 



NATURE 



[May 



1919 



made to do systematic work with these instru- 

 ments, nor would it have been of the slig^htest 

 use to employ them for anything- but lecture- 

 demonstrations. In 1728 or 1729 Jai Singh sent 

 Figueredo, a Portuguese Jesuit, to Europe to 

 procure astronomical tables, and he brought back 

 "tables published under the name ' Lir, ' " i.e. 

 the tables of La Hire. Mr. Kaye also thinks that 

 Jai Singh possessed the " Historia Coelestis " of 

 Flamsteed, and says (p. 69) that "he must have 

 beeh acquainted with the teaching- of Kepler, 

 Galileo, and Newton, for he possessed the works 

 of La Hire, Flamsteed, and others." But neither 

 of these works could g^ive the slig^htest clue to 

 the teaching- of European astronomers. The " His- 

 toria Coelestis " contains Flamsteed 's observations 

 and the resulting- star-catalogue (as well as re- 

 prints of previous catalogTjes), and La Hire's 

 planetary tables are not founded on any theory, 

 but were constructed in an empirical manner, as 

 to the details of which nothing is known. Mr. 

 Kaye sugg-ests (p. 90) that as Jai Sing-h's Euro- 

 pean advisers were chiefly Roman Catholic priests, 

 the development of astronomy since Copernicus 

 must have been discredited in his eyes. This 

 suggestion is of course quite unwarranted, as 

 there were plenty of priests in those days who 

 did good work in astronomy. 



J. L. E. Dreyer. 



THE OCCLUSION OF GASES BY METALS. 

 PRESIDING at the meeting of the Faraday 

 ^ Society in November last, at which the 

 subject of the occlusion of gases by metals was 

 discussed. Sir Robert Hadfield delivered an intro- 

 ductory address, which is about to be published 

 by the society with an account of the dis- 

 cussion. It appears from the bibliography 

 attached to this address that Thomas Graham 

 was one of the first to investigate this 

 subject. His results were published in the 

 Philosophical Transactions of the Royal Society 

 in 1867, the title of the paper being "The 

 Occlusion of Gases by Meteoric Iron." The par- 

 ticular specimen investigated contained 90-9 per 

 cent, of iron, 8*45 per cent, of nickel, and a small 

 quantity of cobalt. It was free from any stony 

 admixture, and was remarkably pure and malle- 

 able. A strip cut from this with a clean chisel 

 was first well washed with a hot solution of 

 potash, then with distilled water, and afterwards 

 dried. It was then placed in a porcelain tube which 

 was evacuated and afterwards heated to redness 

 in a combustion furnace. 



Gas was observed to come off freely, and was 

 collected in successive portions. The first portion 

 evolved consisted principally of hydrogen. Suc- 

 ceeding portions also contained hydrogen as the 

 chief constituent, with smaller quantities of car- 

 bonic oxide and nitrogen. This particular speci- 

 men of iron yielded 2*8 times its own volume of 

 g^as. Graham also investigated the gas taken up 

 by iron from a carbonaceous fire, and in the case 

 of some clean horseshoe nails which he heated in 

 NO. 2583, VOL. 103] 



a similar way he found that the metal yielded 

 2"66 times its own volume of gas, containing 

 about 50 per cent, of carbonic oxide, 35 per cent, 

 of hydrogen, 77 per cent, of carbon dioxide, and 

 7 per cent, of nitrogen. He concluded that as 

 hydrogen was recognised in the spectrum analysis 

 of the lights of the fixed stars, the Lenarto meteo- 

 ric iron which he had investigated came from an 

 atmosphere in which hydrogen was the chief 

 constituent, and that it held imprisoned within it 

 the hydrogen of the stars. 



The latest investigations on the subject of 

 "Occluded Gases in Ferrous Alloys" are those 

 by Allemann and Darlington, whose results are 

 published in the proceedings of the Franklin In- 

 stitute of Philadelphia in February, March, and 

 April of 1918. These investigators describe a gas- 

 tight vacuum furnace which they have constructed 

 capable of continuous service at temperatures of 

 approximately 1900° C. By means of this they 

 claim that all the gases occluded by ferrous alloys 

 may be removed and collected. They have found 

 that hydrogen is most readily set free, that carbon 

 monoxide comes next, . and that nitrogen appears 

 to be held the most tenaciously. As yet they have 

 been unable to determine whether the presence of 

 oxygen in their gases is due to the decomposition 

 of the various oxides of iron or the dissociation of 

 one of the oxides of carbon. Allemann and Dar- 

 lington have found that ferrous alloys may occlude 

 relatively large volumes of gases, in some cases 

 equal to 200 times the volume of the metal, and 

 they suggest that, in addition to the ordinary 

 functions of metals, aluminium, silicon, man- 

 ganese, titanium, and tungsten, when added to 

 molten iron alloys, may either prevent the occlu- 

 sion of large quantities of gases or aid in elimi- 

 nating such gases at lower temperatures than 

 those at which such elimination ordinarily occurs. 

 Finally, they have shown that the removal of these 

 gases markedly changes the microstructure and 

 increases the density of the alloys. 



Sir Robert Hadfield then proceeds to consider 

 the bearing of scientific work of the foregoing 

 kind on the problem of obtaining sound steel, and 

 quotes at some length the views of the late Dr. 

 H^roult as set forth in his paper on "The Pres- 

 ence and Influences of Gases in Steel." Heroult 

 pointed out that the gases obtained from blow- 

 holes in unsound steel ingots always contain 

 hydrogen and nitrogen, often with only traces of 

 carbon monoxide, but it is well known that sound 

 steel, when heated in vacuo, also gives off these 

 gases. It has also been shown that the quantities 

 of gases so liberated are about the same, whether 

 the steel be made by the crucible, the Bessemer, 

 the open hearth, or the electric furnace. In con- 

 sequence of this he concluded that hydrogen and 

 nitrogen are not the cause of the production of 

 blowholes, but that the latter are the result of the 

 liberation of carbon monoxide, except in the case 

 of blowholes near the surface, which are due to 

 the poor condition of the moulds. Hdroult's view 

 of the production of blowholes was as follows : — 

 The carbon monoxide does not pre-exist in the 



