December 12, 1907] 



NA TURE 



141 



out in u review of the early life and struggles of F-'araday 

 Jiow dilVicult it was then to obtain the least help in study 

 compared with the accessible advantages that are so widely 

 -distributed over the country to-day.. The students accord- 

 ingly should fully appreciate their opportunities and use 

 them to the best advantage, not merely as a means for 

 the acquisition of knowledge, valuable and important as 

 this is, and, above all, not as something which may lead 

 to material advancement, but as a means of training the 

 powers possessed by each so as to develop them for action 

 beneficial both to themselves and to their fellows. .A 

 ^hundred years ago men like Faraday, Watt, and Arkwright 

 worked at a time when the world was comparatively young 

 in knowledge ; they had a clean slate to write upon. But 

 while the difficulties of their pioneer .work were enormous, 

 and they started from a position of comparative ignorance 

 of scientific principles, and simple in character as their 

 respective discoveries were, the applications which have 

 ■followed from them have led to a high general level of 

 scientific knowledge to-day which has become the starting 

 ■point for modern conditions of study. Accordingly, if the 

 ■country is to profit by the modern progress of science, the 

 mass of the people must be educated up to this higher 

 plane of knowledge, for it is by intelligent action and 

 ■patient effort and devotion on the part of the rank and 

 file of workers that general advances come. The work of 

 the -Sir John Cass Institute and of similar schools through- 

 out London Is e.xerting a most Important influence in 

 securing this higher level of knowledge for those engaged 

 in work associated with the industries of the country. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, Inne 20 — " On Ihe presence of Sulphur 

 in sonio of the Hotter Stars." By Sir Norman Lockyer, 

 K.C.B., F.R.S. 



In this paper the author gives an account of the dis- 

 covery of the strongest spark lines of sulphur in the 

 spectrum of Rigel. These lines had not previously been 

 traced in any celestial spectrum. It is also shown that 

 two strong sulphur lines (4253-8, 4285-1), which are of 

 abnormal behaviour in the spark and vacuum-tube spectra, 

 are lacking in the Rigel spectrum. They have been found 

 to occur, however, in the Crucian (Bellatrix) and 

 Alnitamian (c Orionis) types of stellar spectra, which re- 

 present higher stages of temperature than the Rigelian 

 ■type. In the tw'o types mentioned the Rigel-sulphur lines 

 arc either lacking or very weak. 



Concisely, the following represents the relative and 

 inverse behaviour of the two sets of lines in stellar 

 spectra : — 





Type 

 Star 



Alnitamian 6 Orioni= 

 'Crucian ...7 Orionis 

 Rigelian ... 3 Orionis 



Sharp Lines 

 (4253 8, 4285-1) 



Present, but weaker 

 than in 6 Orionis 



DlfTuse lii 



Absent 

 Stronge.'t lines pre- 

 sent, but weaker than 

 in /3 Orionis 

 Well shown 



November 7. — " Note on the Association of Helium and 

 Thorium in Minerals." By the Hon. R. J. Strutti 

 F.R.S. 



The question has been often raised of whether or not 

 helium is a product of thorium radio-activity. The author's 

 ■view throughout has been that it is (Roy. Soc. Proc, vol. 

 Ix.xiii., p. 191, 1904, also March 2, 1905). Mr. Boltwood 

 'has recently argued that the helium in radio-active 

 minerals may always be attributed to the action of the 

 uranium-radium series of transformations (.4m. Journ. 

 Sci., vol. xxlii., February, p. 77). In the present note the 

 author directs attention to a case where that view is 

 •clearly untenable. 



Prof. Julius Thomsen, of Copenhagen, described, In 

 1898 (Zcit. physikalischc Chemie, vol. .xxv., part ill.), a 

 helium mineral from Ivitgut, Greenland, similar in some 

 respects to fluor-spar, but containing rare earths. Recently 

 "he has determined the quantity of helium liberated on 



NO igSg, VOL. 77I 



heating as 27 c.c. per kilogram (_IiuU. de I'Acad. Royale 

 des Sciences, Copenhagen, 1904, 53-57). 



Prof. Thomsen kindly sent a supply of this mineral to 

 the author, who has carefully tested it for radium, and finds 

 that it contains no more than the traces which are ubiquit- 

 ous in rocks and minerals. The quantity found was. In fact, 

 about the same as in average rocks, and is insufficient 

 to account for one-hundredth part of tne helium present. 



On the other hand, a solution of the mineral gave 

 abundant thorium emanation. The author is inclined to 

 think that there is some unknown complication about the 

 thorium-emanating power of solutions which makes it un- 

 safe, in certain cases at least, to infer from It the quantity 

 of thorium present ; but enough thorium emanation was 

 given otT by the solution to show that thorium was a sub- 

 stantial constituent of the mineral. He regards it as 

 entirely certain that the helium in this mineral has not been 

 generated in situ by uranium or radium, and has no 

 hesitation in connecting it with the presence of thorium. 



" On the Measurement of Temperatures in the Cylinder 

 of a Gas Engine." by Prof. Callendar, F.R.S., and 

 Prof. W. E. Dalby. 



It is important in the experimental investigation of the 

 internal-combustion engine to be able to measure the 

 temperature at a suitable point in the cycle. 



The difficulty of making this direct measurement arises 

 from the fact that during the cycle of operations in the 

 worl<lng cylinder the temperature rises above the melting 

 point of platinum or of any thermoelectric couple which 

 can be used for the observation. Also, since the tempera- 

 lure is changing so rapidly, whatever apparatus is used to 

 measure the temperature must have small mass ; moreover, 

 its insertion in the cylinder of the engine must not alter 

 the volume or disposition of the clearance space, otherwise 

 there will be danger of pre-ignition. 



The authors use a platinum wire o-oi inch diameter 

 and I inch long in conjunction with a compensator of 

 the same diameter and |-inch long, and the temperature 

 is measured by measuring the change of resistance corre- 

 sponding to the middle |-inch of the i-inch wire. To 

 avoid the difficulty experienced by previous experimenters 

 in this direction, the platinum thermometer is screened 

 from the high temperature by placing it in a valve which 

 allows the thermometer to be exposed during any part of 

 the cycle for a suitable interval of time, and to be perfectly 

 protected from the high temperature when the valve is 

 closed. This valve is contrived in the spindle of the 

 admission valve, and the gear for operating it is clearly 

 shown in the figures in the paper. The advantage of this 

 position is that as the whole charge of air and gas streams 

 Into the cylinder around the spindle of the admission valve 

 the temperature of the valve and the thermometer inserted 

 in it are brought continually into approximation during 

 the whole of the suction stroke, so that at the instant 

 when the contact is made for the measurement of the 

 temperature, namely, just after the close of the admission 

 valve, the thermometer and the temperature it is required 

 to measure do not differ widely in temperature ; moreover, 

 at this point in the cycle the rate of change of the tempera- 

 ture is nearly a minimum. In measurements of this kind 

 it is essential that there should be no missed explosions, 

 and the authors therefore arranged the engine so that this 

 condition should be exactly fulfilled during the whole of 

 the experiments. 



ExperimcMits were made to determine the lag of the 

 platinum thermometer behind the temperature of the fluid 

 it purported to measure, and to determine the effect of the 

 valve carrying the thermometer on the temperature in- 

 dicated by the thermometer. The conclusion arrived at 

 by the authors is that the method may be used to give 

 the temperature of the charge at the beginning of com- 

 pression within 1° C. 



A few experiments were quoted in the paper, from which 

 it appears that at full load the temperature rises to a 

 point between 2000° C. and 2500° C. when the mixture is 

 rich. 



Geological Society, November 6. — Sir Archibald riclkie, 

 K.C.B., Sec.R.S., president, in the chair. — A collection of 

 fossil plants from South .\frica ; Prof. A. C. Seward. 

 The material on which this paper is based was, for the 



