600 REPORT— 1903. 



collaboration with Mr. Ramaffe, a large number of these complicated spectra were 

 photographed at the North-Eastem Steel Works, where the Thomas-Gilchrist 

 process is carried out. The spectra were fully described and measured, with the 

 result that every one of the lines and bands was accounted for. A new line belonging 

 to potassium was discovered to have peculiar properties. Gallium was proved to be 

 present in the Cleveland ore from Yorkshire, in the finished metal, in clays and in 

 all aluminous minerals, even in corundum. Also, by very accurate determinations 

 of the wave-lengths of its principal lines, gallium was proved to be a constituent 

 of the sun. Moreover it was found in several meteorites. Pure gallium oxide 

 was separated, by analytical methods, from iron ores and other materials; and the 

 proportion of the metal in the steel rails made by the North-Eastern Steel 

 Company, of Middlesbrough, was determined and found to be one part in thirty 

 thousand. This Yorkshire steel is richer in gallium than any other substance 

 from which it has been extracted; for instance, the Bensburg blende, supposed 

 hitherto to be the richest ore, contains only one part in fifty thousand. 



By observations on the spectra, the thermo-cbemistry of the Bessemer process 

 of steel manufacture was studied, and the temperatures attained under varying 

 conditions were estimated. The demonstration of the great volatility of most 

 metals, and of many metallic oxides in an undecomposed condition, at the 

 temperature of the oxyhydrogen blowpipe and of the Bessemer flame was of 

 special interest. The metals chiefly referred to are copper, silver, lead, tin, 

 manganese, chromium, iron, cobalt, nickel, palladium, gold, and iridium. Several 

 of these, such as silver and gold, have lately been distilled in vacuo by KrafFt. 



Banded Flame Spectra. 



Well-defined groups of elements yield banded flame spectra which have 

 a similar constitution ; thus magnesium, zinc, and cadmium yield bands composed of 

 fine lines, degraded towards the violet, while fluted band spectra of beryllium, 

 aluminium, and indium were found to be degraded towards the red. Thalliimi 

 also yields a fluted spectrum ; gallium gives a line spectrum ; lanthanum gives 

 bands degraded towards the red ; palladium gives bands in the nature of flutings 

 composed of fine lines ; germanium gave very faint indications of bands ; rhodium 

 and iridium both lines and bands. It became manifest that elements belonging to 

 the same group in the periodic system of classification exhibited banded spectra 

 which are similarly constituted, and hence similarly constituted molecules of the 

 elements have similar modes of vibration, whether at the lower temperature of the 

 flame or at the higher temperature of the arc or spark. Banded spectra are thus 

 shown to be connected with the periodic law. 



A great advantage is to be derived from an investigation of banded spectra 

 from a theoretical point of view, as well as from the application of this method to the 

 analysis of terrestrial matter. While the spectra are easily obtained, they can be 

 applied in a very simple manner to the chemical analysis of minute quantities of 

 material, and may readily be made quantitative. 



M. Armand de Gramont has described a method of obtaining spectra of 

 metals and metalloids by means of a spark, and has given the analysis of eighty- 

 six mineral species. The novelty and importance of his work lies in the method 

 of obtaining spectra of such constituent substances as chlorine, bromine and 

 iodine, sulphur, selenium and tellurium ; also phosphorus and carbon when in a 

 state of combination, as sulphates, phosphates, carbonates, &c. 



There is a possibility of utilising this method for the quantitative determina- 

 tion of carbon, sulphur, and phosphorus in iron and steel during the process of 

 manufacture. 



Definition of an Element. 



In a discussion on the question of the elementary character of argon in 1895 

 it was pointed out by me that argon gave a distinct spark spectrum by the action 

 of condensed sparks, and therefore, on this evidence alone, it must be regarded as 

 an element. The fact that it gave two spectra under different conditions was not 



