PECULIAE ACCBETIONS. 



731 



Peculiar accretion found at Gage, Hagaman & Co.'s smelter This accretion was a thill, 



compact, yellowish-green mass of alternate layers of sulphide of lead and yellowish- 

 green oxides ; it contained only a very few grains of lead in flue particles. This 

 accretion is remarkable on account of the enormous quantity of zinc concentrated in it 

 (53 per cent.), chiefly in the state of oxide (G5.5 per cent.). It is also the only accre- 

 tion in which were found traces of chlorine, bromine, and iodine. The rational report 

 of the analysis has been arranged so as to show as clearly as possible how the differ- 

 ent substances are mixed or combined. Sulphide of zinc was estimated by means of 

 the sulphureted hydrogen evolved on treating the accretion with weak sulphuric acid. 

 No iron was present in the solution. 



Traces of the silver reported as chloride exist in the state of sulphide. 



ANALYSIS XL1V. PECULIAIS ACCRETIONS. 



SECTION V. 

 THEORETICAL DISCUSSION. 



REACTIONS IN THE BLAST-FURNACES. 



To form a correct conception of the metallurgical reactions iu the blast-furnaces 

 of Leadville we must take into consideration 



(1) The great altitude at which the smelting operations take place, which modi- 

 fies to a considerable extent the volume of the blast and the volatility of volatile com- 

 pounds. 



(2) The manner in which the smelting charges are disposed in the furnace. It 

 has been seen already that the ores and fluxes are placed between two layers of fuel, 

 so that iu all the zones of the furnace above those of agglomeration and fusion the 

 reactions take place by actions of gases upon solid substances, and that in a very 

 limited space only reactions by contact of solid matter can take place. 



