93 



only possible by the aid of the Spectroscope to determine the kind of 

 element we are examining, but that he can actually determine the relative 

 quantity, that is, he can perform a c^uantitative as well as a qualitative 

 analysis by its means. 



But I may be permitted to call your attention to a more homely field 

 of investigation with the Spectroscope, in which much yet remains to be 

 done. I refer to the investigation of the nature of the flame from the 

 Bessemer convertor. As many of you know, this flame is of a most 

 intense character, throwing a shadow in broad day light, and when ex- 

 amined by the Spectroscope we see one of the most beautiful spectra I 

 know of. The flame is mostly due to the combustion of carbon, but it 

 differs in a remarkable manner from other cai-bon spectra, and even when 

 we collect the carbonic oxide as it comes from the convertor (as I have 

 done) and burn it at leisure, we get quite a different spectrum ; so that 

 although many have worked slightly at the subject, and we know that the 

 ' bloiv'' should be stopped when all the gi-een and red lines disappear, 

 (as they do suddenly) and although some years ago I even got so far as 

 to find that we could predict the duration of the blow from a given 

 point, very much remains iinexplained. Those persons who, like myself, 

 have to conduct the large operations of extensive works, have little time 

 for devoting themselves to a subject which requires constant and close 

 attention, while other workers in science have been attracted to the more 

 wonderful phenomena of stellar analysis. I shall be happy however 

 to give our members an opportunity at any time of witnessing the 

 Bessemer spectrum, as we can generally promise that there will be a 

 ~ " blow" going on at West Cumberland, at least every hour day and night. 

 I will now attempt to show you on the screen, the spectra of one or 

 two of the heavy metals, but I must point out to you that the spectra of 

 these, as of many other bodies, are far better examined by taking the 

 induction spark between two jDieces used as the j^oles, and that the ex- 

 hibition on the screen is coarse and rough compared with the beauty of 

 the spectrum seen through such instruments as are on the table for your 

 inspection. 



I have endeavoured in the short time at my disposal to give you 



