TRANSACTIONS OF SECTION B. 489 



Per-centage. 



Selenium 10'6 



Tellurium 1-2 



Sulphur, elemental 6'5 



Earthy insoluble matters 24-4 



Lead sulphate 29"6 



Sulphiu'ic acid ....... 



Water 



Oreranie matters , ,.«. ^„ „ 



Arlenic . ^^y ^'^- 27-9 



Iron, a very little j 



A non-identified substance . . . .J 



100-0 

 The point which will attract attention in this analysis is that, whereas the 

 quantity of tellurium is to that of the selenium as 5 to 2 in the sulphur, and as 5'5 to 

 2 in the liquid with the deposit, it is only as 1 to 9 in the solid part of the deposit. 

 The explanation of this discrepancy is simple. They find by experiments with the 

 deposit itself and by others with pure tellurium, that tellurium in the finely divided 

 state readily oxidises in water exposed to air, and much more rapidly in the 

 presence of acid than not, whereas selenium is not sensibly afiiected. Therefore 

 the deposit, exposed as it had been to the air, contained much selenium with but 

 little tellurium, most of the tellurium having oxidised and gone into solution in the 

 liquid. It was to avoid further dissolution of the tellurium that they did not wash 

 the deposit for analysis. 



The deposit is of a grey-red colour, with a few bright yellow points, probably 

 orpiment, as yellow selenium sulphide is not permanent. On distilling the air- 

 dried deposit in clay retorts they foimd that the tellurium as well as the selenium all 

 distilled over. Much water and sulphur dioxide were given ofl', and at first also 

 a bright yellow sublimate, believed to be orpiment. The contents of the retort, 

 where the temperature had not been too high, contained galena, formed during the 

 heating, possessing a strong metallic lustre and marked crvstalline form. 



FBIDAY, AUGUSl 25. 

 The following Reports and Papers were read : — 



1. Report of tJie Committee appointed to investigate hy means of Photo- 



graphj the Ultra-VioJet Spark Spectra emitted hy Mefnllic Elements, 

 and their combinations binder varying conditions. — See Reports, p. 143. 



2. Report of the Committee appointed to prepare a new series of Tables of 



Wave Lengths of the Spectra of the Elements. — See Reports, p. 144. 



3. On the application of the Diamond to Mineralogical and Chemical 



Analysis. By Professor yon Badmhauer. 



The author referred to his earlier memoirs on carbon in its three states, viz. : 

 (1) the octahedral transparent diamond; (2) the apparently amorphous black 

 diamond or carbon; and (3) the globular diamond or lort, in which he had de- 

 monstrated the second to be an agglomerate of small crystals cemented together 

 probably by hydrous oxide of iron, thus standing in much the same relation 

 to the first as does sandstone to quartz, while the bort shows confused crystal- 

 lisation and so is related to the first as calcedony to quartz. He referred also 

 to the application of carbon to economic purposes, such as drilling rocks, and to 



