$46 



NATURE 



[February 13, 1896 



an entirely different standpoint, arrived at exactly the 

 same conclusion. They recognised two gases, one repre- 

 sented by D^, the other by 667, and further they showed 

 that the Hnes might be arranged into six similar and 

 beautifully rhythmic series, a principal and first and 

 second series for each gas. These are indicated in the 

 diagram of Bellatrix on p. 345, and in Fig. 14 ; He = helium 

 is the gas which contains D^, the other gas I so far call 

 "gasX."i 



This result is, however, more important from the 

 chemical than from the astronomical point of view at 

 jtresenf. 



A word in conclusion referring to the occurrence of 

 this gas in terrestrial minerals. 



We are brought face to face with one question, which 

 ought to influence many lines of work for many years to 

 come. I have already suggested to you that we really 

 now can talk with something like certainty 

 and definiteness about hot stars and cooler 

 stars, and that in the hottest stars we r - - 

 know of, the atmospheres of those stars =*- « 



consist almost entirely of hydrogen and I 



helium. ■ 



But see what a little trace of helium we 

 have in this small planet of ours, which un- 

 doubtedly was once a sun, which undoubtedly 

 once had an atmosphere just as glorious in 

 its hydrogen and its helium as any of the 

 other stars are now glorious. 



What has become of that helium ? This ijj 1 t 1 

 question will have to be very carefully con- 1 

 sidered in the next few years. 



We appear to be in presence of the 

 vera causa, not of two or three, but of 



many of the lines which so far have :__ 



been classed as " unknown " by students -*'«.-" 



both of solar and stellar chemistry, and we 



are also apparently in the presence of a new ^'^^ '4- 



order of gases of the highest importance 



to celestial chemistry, though perhaps they 



may be of small practical value to chemists, because their 



compounds and associated elements are for the most 



part hidden deep in the earth's interior. Why do I 



suggest a new order of gases ? Look at the facts. 



AH the old terrestrial gases, with the exception of 

 hydrogen, are spectroscopically invisible in the sun and 

 stars — though they doubtless exist there — and these new 

 gases, scarcely yet ghmpsed, have already supplied us 

 with many points of contact between our own planet 

 and the hottest part of our central luminary that we can 

 get at, and stars like Bellatrix. 



The work certainly is full of hope for the future, not 

 only in relation to the possibility of more closely corre- 

 lating celestial and terrestrial phenomena, but since it 

 indicates that terrestrial chemistry, founded on low 

 density surface products in which non-solar gases largely 

 enter, is capable of almost infinite expansion when the 

 actions and reactions of the new order of gases, almost, 

 it may be said, of paramount importance in certain stages 

 of stellar evolution, shall have been completely studied. 



I have some other results to refer to, but it is quite 

 sufficient, I think, to leave my story as I have told it to 

 you without going back on any of the characters, or 

 without dealing in any greater detail with the denouement 

 of the plot. 



1 In the many comparisons I had to make, I soon found the inconvenience 

 of not having a name for the gas which gave 667, 501, and other lines. 

 When, therefore, Profs. Runge and Paschen, who had endorsed my results, 

 and had extended them, called upon me, I thought it right to suggest to 

 them that, sinking the priority of my own results, we should all three 

 combine in suggesting a name. Prof. Runge (under date October 20) wrote 

 me, " the inference that there are two gases is a spectroscopical one, being 

 based on the investigation of the ' series.' Now, though we think this 

 basis quite sound, we must own that the conclusion rests on induction. . . . 

 For this reason we do not want to give a name to ' gas X.' " I have so far 

 suggested no name, though Orionium and Asterium have been in my mind. 



NO. 1372, VOL. 53] 



But the story has a moral. The more we can study 

 the different branches of science in their relation to each 

 other, the better for the progress of all the sciences. 

 Another point is, that in the study of nature we behave in 

 a very foolish way if we think there is anything unim- 

 portant which comes under our eyes. If it had so 

 happened th2itT>r. Hillebrand had seen the line spectrum 

 of nitrogen in 1888, we should have saved all these seven 

 years of waiting for this terrestrial source of helium ; and 

 I may add, further, that argon would have been discovered 

 as well in the first hour's work. In science, results of the 

 first importance depend upon the minute examination of 

 so-called residual phenomena ; it is too much the general 

 tendency, of scientific work on a large scale, to think 

 too much of those results which may have a practical 

 importance. 



Geologists, natural philosophers generally, have been 



\ 



Runge and Paschen s results suggesting that clevelte gives off two gases, 

 each with three series of lines. 



familiar with the mineral world for a considerable number 

 of years. What have they been doing all the time ? They 

 have confined their attention too exclusively to the con- 

 tained metals, and have neglected the gases ; whereas it 

 now seems that if they had been less careful of the metals, 

 and had studied the gases, it would have been very much 

 better for our nineteenth century knowledge. And that is 

 the moral of my simple story. 



J. Norman Lockyer. 



SCIENCE TEACHING IN SECONDARE 

 SCHOOLS. 



THE School Syllabus of Chemistry and Physics, 

 which has just been put forward by a Committee 

 of the Incorporated Association of Headmasters, is an 

 attempt to indicate to those who are dissatisfied with the 

 ordinary course of qualitative analysis, the lines on which 

 the practical study of science may be made more 

 profitable. 



It is a great misfortune that in constructing a syllabus 

 for use in schools, one has constantly to keep in mind its 

 relation to the examination fiend. A short notice upon 

 this syllabus, in this journal on Jan. 16 (p. 262), contained 

 the observation that the teaching in schools is governed 

 entirely by the examinations ; and nothing could be more 

 sadly true, nor a greater hindrance to a more rational 

 system of teaching. 



A syllabus may be perfect of its kind, but school 

 authorities do not ask " How will it develop certain 

 powers?" but "How will it examine?" and they base 

 their estimation of it upon the answer to this question ; 

 while the relative value of the two in the eyes of parents 



