714 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



Discussion. Both samples of chamber-dust were examined very carefully for flu- 

 orine. If this substance existed in the camp it is here that it would be concentrated; 

 but no trace even was detected. Some estimations were made of both selenium and 

 tellurium, but the results were considered as too high, and traces only are reported. 

 The estimation of both these substances in such mixtures as those of the flue-dust is 

 too complicated, when traces only are in question, to devote much time to it. However, 

 both selenium and tellurium have been handled in small quantities, and the writer 

 feels perfectly sure of their existence. He also feels assured that both exist in the 

 state of seleuious and tellurous acids. It is a somewhat singular fact that baryta 

 was carried in the fumes in the state of silicate of baryta, a trace only of sulphate of 

 baryta being found. One is almost tempted to come to the conclusion that certain 

 silicates are volatile. 



The sulphides of iron, zinc, And manganese were estimated by means of the 

 quantity of sulphureted hydrogen evolved when the dust is treated by weak .acids. No 

 molybdenum could be detected, although it will be seen that it is constantly present 

 in the blast furnaces. Cadmium could not be estimated by the classical methods, and 

 it was in examining the zinc obtained in the course of the analysis that this metal was 

 found. The formula of the oxychloride of lead found in the portion of the dust solu- 

 ble in water is 3PbO, PbCl 2 , the oxybroniide and iodide having the same formula. 



In all probability the chloro-broino-iodide of lead found in the portion of the 

 fumes insoluble in water and soluble in acids exists in combination with a very large 

 excess of oxide of lead, and also in combination with phosphate and sulphide of lead. 

 The fumes were not examined spectroscopically for indium and thallium, so that there 

 is some doubt about the presence of these metals. However, the writer is almost cer- 

 tain that he has perceived the characteristic oxysulphide of indium and observed in 

 several instances the green flame of thallium. 



The now metal which the writer was fortunate enough to observe and to trace 

 out in all the fumes has only been seen in such minute quantities that further inves- 

 tigation on quite a large scale is absolutely necessary, in order to isolate it, to study 

 its properties, and to place its existence beyond doubt. It has been possible, however, 

 to find already three characteristic properties : 



1. The oxide of the new metal gives a beautiful blue color to a bead of borax 

 placed in the ordinary flame of the blow-pipe, and the bead becomes perfectly color- 

 less in the reduction flame. 



2. The sulphide of the new metal is slightly soluble in sulphide of ammonium, 

 and the solution takes a characteristic blue tinge. 



3. The iodide of the new metal has a flue rich pink color when in solution. 



It may also be added that in one instance the sulphide of the new metal was 

 obtained in a state of great purity, and that this sulphide was very fusible and had 

 a deep brown color. 



Although a great many substances are carried away physically in virtue of their 

 volatility, and others mechanically by the force of the blast, it seems pretty clear from 

 the inspection of the analyses that some very complicated reactions take place in the 

 furnace, by means of which some substances are carried away in the state of volatile 

 compounds and deposited in the dust in their original non-volatile form. In all prob- 

 ability copper, titanic acid, tin, aluminium, magnesium, and silicium are carried away 



