171 Mr. J. N. Lockyer on Recent 



Abney himself. We find, now, that Mr. Rutherfurd has 

 given ns an engine of such enormous power that the fine- 

 ness of the collodion film is entirely distanced ; that is to say, 

 we can get from these perfect gratings spectra so extremely 

 fine and so full of detail, that they can be enlarged until the 

 structure of the ordinary collodion comes in and prevents a 

 fine picture. But if instead of the ordinary collodion process, 

 those which are being worked out with such success by Cap- 

 tain Abney be employed, then it appears that the film is as 

 perfect a thing in its way as the grating is in its way, and 

 one can go on obtaining any magnification one wants. 



This is a photograph of the H lines obtained by the grating 

 and film to which I have referred. Between the H and K lines, 

 where the eye sees faintly three lines, there are now nearly 

 a hundred ; and that will speak more than any words of 

 mine as to the extreme importance of the introduction of pho- 

 tography in such a research as this. Now here there are no 

 bright lines ; but, very conveniently, this next photograph con- 

 tains one of the bright lines discovered and carefully recorded 

 by Cornu, who has recorded bright lines in the ordinary 

 solar spectrum as well as Hennessy. In exactly the middle 

 of the field now is the bright line recorded as a bright line by 

 Cornu in his map of the blue end of the solar spectrum ; but 

 excepting that one bright line, which is much more intense than 

 any other part of the spectrum, bright lines are non-existent. 



During the course of last year Dr. Draper, of New York, 

 published the first results of a research which he has undertaken, 

 going over very much the same ground with regard to the 

 metalloids as had been gone over in this country with regard 

 to the metals. Dr. Draper, who has long been known as a 

 most earnest student of science, approached this subject with 

 a wealth of instrumental means almost beyond precedent; and 

 his well-known skill and assiduity, in the course of the two or 

 three years during which his work was carried on, enabled him 

 to accumulate facts of the very greatest importance. I am 

 most anxious to make these preliminary remarks, and to state 

 my very highest respect for Dr. Draper, because in referring 

 to his work I shall have to point out that some of his results 

 are, in my opinion, not yet completely established. Dr. Draper, 

 in the first instance, claims the discovery of the bright lines 

 already referred to, and bases a new theory upon them. It is by 

 no means as a stickler for priority that I regard this as a very 

 great pity, but because I think that, if the very considerable 

 literature touching these bright lines (papers by Young, Cornu, 

 Hennessy, Secchi, and others) had been before Dr. Draper 

 when his paper was written, the necessity for the establish- 

 ment of a new theory of the solar spectrum, which doubtless 



