TRANSACTIONS OF SECTION B. 599 



previously arrived at by Emerson Reynolds, that the atomic mass of beryllium 

 was not ]3'8 but 9-2. 



The next practical application of the spark spectra was to the analysis of 

 rhabdophane, a mineral found many years ago in Cornwall and described by 

 Heuland in 1837 as a zinc blende of a peculiar character. 



This mineral I found to contain neither zinc nor sulphur, and therefore it is 

 not a blende. It is, in fact, a phosphate of the formula R,^03.P205.2H20, in which 

 the oxides of cerium, didymium, lanthanum, and yttrium may wholly or in part 

 replace each other. The didymium absorption spectrum is well seen both by 

 reflection from the surface and transmission through thin sections of the mineral. 

 The spark spectrum of the yttrium chloride obtained from rhabdophane was 

 compared with that observed by Thalen and ascribed to yttrium. Of the fifty-one 

 lines in the spectrum of yttrium thirty-eight were absent from the yttrium 

 obtained from rhabdophane, and it was concluded that the purest yttrium was 

 that which yielded the simplest spectrum. This was the first occasion of the 

 finding of yttrium in any British mineral. Quite recently a confirmation of this 

 ■view has been obtained by comparing this spectrum with lists of the arc lines of 

 yttrium and ytterbium which have just been published by Kajser (1903). 



Penfield analysed a mineral found in the United States which he named 

 scovellite : it proved to be identical in species with rhabdophane. 



Flame Sjiectj-a at High Temperatures. 



What are commonly known in the chemical laboratory as flame spectra are 

 chiefly those of the metals of the alkalies and alkaline earths ; also of gallium, 

 indium, and thallium. The researches of Mitscherlich and Lecocq de Boisbaudran 

 first showed that copper, manganese, and gold gave flame spectra. Lockyer, 

 Gouy, and Marshall Watts also investigated flame spectra. 



In 1887 I used iridium wires one millimetre thick, twisted into loops upon which 

 fragments of minerals were heated in the oxygen blowpipe flame. Natural silicates 

 yielded spectra not only of alkalies but of the alkaline earths, and also distinct man- 

 ganese spectra. Baryta, strontia, and lime gave spectra when insoluble compounds 

 such as the sulphates were thus examined at high temperatures. Iron, cobalt, and 

 nickel gave spectra even when compounds such as the oxides were heated strongly. 

 But iridium, though infusible, is somewhat volatile, and contributes a line spectrum 

 to the flame. In 1890 thin slips of the mineral kyanite and even pieces of tobacco 

 pipe were used instead. Experience with this method of working went to show 

 how the flame spectra of oxides of calcium, strontium, and barium could be sepa- 

 rated from those of lithium, sodium, potassium, rubidium, and csesium, as observed 

 in the Bunsen flame. Furthermore, that even the most volatile of these substances 

 could be made to yield a continuous coloration from a single bead of salt for a 

 period exceeding fifteen minutes, and extending to one or two hours, so that 

 measurements of the lines might be made with some degree of certainty. 



In order to study the flames emitted from furnaces during metallurgical 

 operations, and particularly from the mouth of Bessemer vessels, it became 

 necessary to ascertain what really were the lines of the elements observed under 

 diffierent conditions at a high temperature, and accordingly systematic methods of 

 study were developed from the previous somewhat tentative experiments. 



In all the flame spectra obtained by the oxyhydrogen blowpipe the ultra-violet 

 line spectrum emitted by water vapour which had been discovered by Huggine 

 and by Liveing and Dewar was visible on the photographs by reason of the 

 combustion of the hydrogen in the hydrocarbon, cr the hydrogen gas itself, when 

 burnt along with oxygen. The flame spectra are always shorter than those 

 obtained from the arc or from condensed sparks. After an extended examination 

 of spectra produced by the oxyhydrogen blowpipe from solid substances, the 

 knowledge obtahied was applied to the examination of the flames coming from the 

 Bessemer vessel during the ' blow ' during all periods from the commencement to 

 the termination. These observations were made at the London and North- 

 western Railway Steel Works at Crewe ; and at Dowlais, in South Wales. In 



