472 



NA TURE 



[Alarc/i 1 8, 1886 



your attention to the fact that we found inversions, as they are 

 now called ; that is to say, to take an instance, if we repre- 

 sent three lines of a spectrum by a, b, and c, we have found among 

 the most widened lines in spots a without b and c, b without a 

 and c, and c without a and /'. Now that is a condition of things 

 impossible to understand or explain on the old view. 



We next continued the discussion over another region of the 

 spectrum, and we found that the result held absolutely good, that 

 is to say, in other regions we got these same inversions. If 

 we look at a map belonging to another period, although the lines 

 change, the inversions remain, and the lines behave very much in 

 the same way as the other. This result is quite constant for all 

 regions of the spectrum examined. Hence, finally, we learn that 

 these inversions hold good for different periods, and for different 

 parts of the spectrum ; and we have found that spectroscopic- 

 ally any one vapour in the spots behaved in exactly the same 

 way as various mixtures of many vapours would be bound 

 to do. 



The result of this inquiry with regard to cliemical substances 

 which have been most carefully worked out, is indicated in the 

 accompanying table, giving the result of the work for two years 

 from 200 spots. 



Statistics of the most H'iiiencd Lines seen in 200 Sunspols at 

 Kensington 



In these 20J spots out of 172 lines of iron which we might 

 have seen only 72 were observed altogether ; out of 120 lines of 

 titanium which we might have seen only 38 were seen ; and then 

 the number goes on decreasing : 24 in the case of nickel, of 

 which 9 were seen ; 19 in the case of zinc, of which 5 were 

 seen ; 13 of magnesium, of which 4 were seen ; 12 of platinum, 

 of which I was seen, and so on. 



The final upshot is, therefore, that at the spot-level we do not 

 see the Fraunhofer spectrum, as we ought to do on the old theory. 

 What we do see is a small percentage of the lines, and we see 

 them under conditions which are entirely unexpected. No one, 

 I think, who knew anything about spectrum analysis would have 

 anticipated the result which we have got at Kensington in these 

 700 observations. 



These, though the earlier results, are not the only results which 

 we may hope to get by going on with the work. At present we 

 have limited ourselves to recording the dates of the spots. Hut 

 this is not enough ; we must know the actual positions of the 

 spots on the sun. We must note wliether each particular spot is 

 in the northern hemisphere or in the southern hemisphere, with 

 the view of determining whether there is any chemical difference 

 between the north part of the sun and the south part ; and then 

 again we .shall have to compare the latitudes of spots, with tlie 

 view of determining whether there is any difference in the 

 chemistry of the spots according to the latitude. I may tell you 

 that we are working at that particular point just now, and it 

 really does look as if the sudden changes in the spectra recorded 

 may have been due to the fact that the spots compared were 

 spots varying very considerably in latitude, and it would not 

 surprise me to find that spots which are very like each other in 

 their spectra will be found to be situated more or less in the same 

 degree of latitude, — whether the same degree of latitude north 

 or south we do not know. And there is another question, 

 too. I pointed out that there is a considerable number of 

 lines seen in the s]-)ectrum of the arc which are left out of the 

 spectrum of the spark. Now, will that help us at all in our in- 

 quiries? I think perhaps it may. Everybody assumes that the 



electric spark is hotter than the electric arc. If that be so, the 

 lines which we see .at the temperature of the arc, and which we 

 do not see at the temperature of the arc only, m.ay represent the 

 lines due to cooler vapours — more complex molecular groupings 

 it may be, which can exist in the cooler temperature, but which 

 entirely break up on the application of a higher one. If that be 

 so we shall be able to sort out the spots more or less according 

 to their temperature. 



Though the results have not been shown on the maps, 

 the lines visible in the spectrum of some substances at the 

 temperature of the oxy-hydrogen jet have been observed. 

 Everybody assumes that the temperature of the o.\y-hydrogen 

 jet is lower than the temperature of the electric arc or 

 spark ; so that, if we can get a spot which gives us those 

 lines thickened only which we see at the tejnperature of the 

 oxy-hydrogen jet, we should be perfectly justified, I think, in 

 saying that th.at was a relatively cool spot ; whereas, if we saw a 

 spot which only had those lines thickened which are intensified 

 on the passage from the temperature of the arc to the tempera- 

 ture of the spark, we should be justified in saying that that 

 spot was very much hotter. I only throw this out as an indica- 

 tion of the kind of result which probably future working and 

 future thought will bring out, and that we are by no means at 

 the end of the work 5'et. 



J. Norman Lockyer 

 ( To be continned. ) 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



( ).\FOKD. — The new Medical Statute was finally approved by 

 Convocation on March 16. The scope of the new Statute .and 

 its bearing on the study of medicine at Oxford were so clearly 

 described by Prof. Burdon-Sanderson in last week's Nature, 

 that it is unnecessary to refer further to them. One point in- 

 sisted on by the Professor, that the present student of medicine 

 wastes his first year over Pass Moderations, has not yet been 

 corrected. The Moderations Committee are still deliberating, 

 but there seems little doubt that students of Natural Science in 

 Oxford will receive substantial relief under the new scheme. 



The present year is one of reform. While the Moderations 

 question is still under debate, a new and much-needed reform has 

 been sprung upon the University. The old Examination in the 

 Rudiments of Faith and Religion has by common assent become 

 out of date. Last week the preamble of a new Statute was 

 passed nemine contradicente in Congregation. We must wait till 

 next term to learn the fate of the Statute itself It seems time 

 that the University should grant degrees without demanding an 

 intimate knowledge of the Thirty-nine Articles. 



Cambridge. — It has been decided to establish a Tripos 

 Examination in Engineering, to be combined with the present 

 Natural Sciences Tripos. The general basis is that, as an 

 alternative to the present First Part of the Tripos, an examina- 

 tion in certain mathematical subjects useful in engineering, 

 physics, chemistry, and theory of structures shall be held, to be 

 followed by a practical examination. Those who pass this will 

 be entitled to a degree in honours. A later examination, con- 

 current with the second part of the Natural Sciences Tripos, is 

 to consist of advanced papers in Physics, Chemistry, and 

 Engineering, distinction in one or more of which is to entitle a 

 student to a first class. When the complete scheme is published 

 we shall give full details. 



SCIENTIFIC SERIALS 

 The Journal of Physiology for November 1885, vol. vi. No. 6, 

 contains : — On a double differential rheotome, by Dr. W. D. 

 Samways (plate 7)- The instrument is described and figured — 

 On the blood of Decap:id Cnistacea, by Dr. W. D. Haliburton 

 (plate 8). Assisted in part by a grant from the British Medical 

 Association, the author has studied the blood in the lobster, the 

 edible crab, the crayfish, Astacus, and Nephrops itorve^icus ; and 

 he treats of its colour, constituents, and coagulation. He ascribes 

 the clot as due to the formation of a body scarcely to be dis- 

 tinguished from the fibrin of vertebrate blood, and believes that 

 its formation is due to a ferment action, which latter is derived 

 from the amoeboid corpuscles of the blood. At the close of the 

 memoir the author treats of the comparative aspects of crustacean 



