718 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



ANALYSIS XXXVI. FUMES FROM BARTLETT FILTER Continued. 

 national. 



Discuasion. The combinations in which lead exists in these fumes and their vola- 

 tility is most remarkable. To appreciate this fully one must remember that the fumes 

 were filtered at a distance of nearly 200 feet from the blast furnace. The above 

 analysis shows, besides 9 per cent, of chloro-bromo-iodide of lead, 18 per cent, of 

 sulphides iu combination with the chloro bromo-iodides, and 11 to 12 per cent, of 

 phosphate of lead, proving a most surprising volatility for the two latter combinations. 

 The percentage of lead as oxide is relatively low as compared with other dusts. Itis most 

 worthy of remark that the iron, manganese, zinc, and cadmium must be in the state 

 of sulphides and also have an unusual degree of volatility. That these fumes should 

 be richer in arsenious acid than the ordinary chamber dust might have been expected, 

 but that they should have carried off tin and titanic acid is most remarkable. Silica 

 being combined with the lead as silicate of lead shows that this combination is al.-o 

 volatile. 



