MATTES. 



725 



Assays of mattes Crude mattes generally contain variable quantities of metallic 

 grains, so that whenever it was thought advisable the crude matte was assayed, as well 

 as the powder and metallic grains separated by the sieve. The following assays were 

 made in the laboratory of the Survey. 



TABLE XIV. ASSAYS OF MATTES. 



No. 1. American smelter, lead matte. 



No. 2. Billing &. Eilers's smelter, lead matte, blackish gray. 

 No. 3. Camming & Finn's smelter, lead and iron matte. 

 No. 4. Elgin smelter, lead matte, grayish. 



Discussion. It has been seen (Analysis XL) that the normal iron matte contains 

 85 ounces of silver, and that (assay of mattes No. 3) the powder of a similar matte 

 from the same smelter contains 8GJ ounces. The normal lead matte (Analysis XLI) 

 contains 70 ounces of silver, and the powder from similar mattes at the same and 

 at other smelters contains 06.25 ounces of silver (No. 4), 45.5 ounces (No. 1), 74.35 ounces 

 (No. 2). 



The relation between the contents of bullion (represented by the metallic grains) 

 in silver and the contents of the mattes in silver is rather peculiar. In No. 1, the 

 richest bullion. 163 ounces, corresponds to the poorest matte; and in No. 3, the poor- 

 est bullion, 146.V ounces, accompanies the richest matte, 86 ounces. -Evidently there 

 is an antagonism between matte and bullion, in which the latter has not always the 

 advantage. 



ACCRETIONS. 



There are two kinds of accretions formed in the blast furnace which have noth- 

 ing in common : the hearth accretions and the shaft accretions. 



Hearth accretions. Hearth accretions are, in general, very similar to mattes, but 

 sometimes they look more like slags. From a very rough examination of these prod- 

 ucts, it results that they are chiefly formed of slag, and lead- and iron-matte, and it 

 is thought that the word slag-matte is the most appropriate to designate them. They 

 are formed of variable quantities of slag and matte, but often contain nearly equal 

 parts of both, and represent in the highest degree those singular compounds, crystallo- 

 graphically combined, which have been described so often in this report. 



