COMPOSITION OF CHAMBER DUST. 



711 



peeled by the smelters, who were under the impression that there was 110 difl'ereuee 

 between the different parts of the same cake of slag, and who used the ingenious 

 process of shelling out as a convenient way of breaking up the slag in small pieces 

 before resineltiug. 



A comparison between specimens 28, 29, 30, and 31, or dolomitic slags, and speci- 

 mens 32, 33, 34, and 35, or calcitic slags, shows that both kinds of slag contain sen- 

 sibly the same amount of silver. 



CHAMBER-DUST. 



The flue and chamber dust of Leadville is always in the form of a coarse reddish 

 or blackish powder and full of very small particles of charcoal and coke. 



Very little has been done in Leadville with regard to a thorough examination of 

 these products, and all the information which could be obtained bears on the estima- 

 tion of lead and silver, and occasionally of silica and iron. In the following table is 

 condensed such information as could be obtained : 



TABLE XII. Assays cf chamber-dust. 



In the description of each smelter the amount of flue-dust caught and the methods 

 of treatment of flue and chamber dust have already been given. 



Analysis. An examination of the flue and chamber dust of the blast furnaces of 

 Leadville afforded such a fine opportunity for detecting most of the substances dis- 

 seminated in the camp that the writer carried on quite exhaustive researches on these 

 products, and in order not to let anything escape he treated the dust with boiling 

 water aud made a careful analysis of the soluble portion, then a careful examination 

 of the portion soluble in acids, and lastly a complete analysis of the portion insoluble 

 in acids. The results thus obtained are extremely complicated aud present an unnat- 

 ural appearance, but such as they are they give a clearer idea of the form under which 

 the different compounds exist in the fumes, and of the reactions to which they owe 

 their origin, and no attempt was made to simplify the reports. 



The labor expended on the examination of the lead fumes was rewarded by the 

 discovery of a new metal which appears to be distributed widely, though sparingly, 

 throughout the camp. In the elementary analyses the earthy and alkaline metals in 

 combination with metalloids other than oxygen have been reported in the metallic 

 state. 



