[12] Abstract of a paper (“The Mechanical Feeding of Silver-Lead Blast Furnaces”) presented at the Mexican meeting of the American Institute of Mining Engineers and published in the _Transactions_, Vol. XXXII. For the first portion of this paper see the preceding article. [13] Abstract of a paper in _Western Chemist and Metallurgist_, I, VII, Aug., 1905. [14] Much better work is being done at present, smelting the Western zinc ores, and the residue contains about one-third of the above figure, or 7.5 per cent. of zinc oxide. The high per cent. of ZnO left in residue was mainly due to poor roasting. [15] There was also considerable coke used of an inferior grade, made from Kansas coal. [16] Part of the ZnO in roasted matte came from being roasted in the same furnace the zinc ore had been roasted in. [17] There was less residue on the charges during this month, which accounts for the larger tonnage with a lower blast. [18] Translation of a paper read before the Naturwissenschaftlicher Verein at Aachen, and published in _Metallurgie_, 1905, II, i, 1-6. [19] 35 to 40 cm. = 13.78 to 15.75 in. = 8 to 9.12 oz. per sq. in. [20] _Engineering and Mining Journal_, 1904, LXXVIII, p. 630; article by Donald Clark; reprinted in this work, p. 144. [21] Owner of the patents.—EDITOR. [22] Abstract of a paper in _Metallurgie_, II, 18, Sept. 22, 1905, p. 433. [23] This method is described further on in this book. [24] Translated from _Metallurgie_, Vol. II, No. 19. [25] British patent, No. 17,580, Jan. 30, 1902, “Improved process for desulphurizing sulphide ores.” [26] W. C. Roberts-Austen, “An Introduction to the Study of Metallurgy,” London, 1902. [27] A. Lodin, _Comptes rendus_, 1895, CXX, 1164-1167; _Berg. u. Hüttenm. Ztg._, 1903, p. 63. [28] _Comptes rendus_, loc. cit. [29] Translated from the _Zeitschrift für das Berg.-Hütten-und Salinenwesen im. preuss. Staate_, 1905, LIII, ii, pp. 219-230. [30] Translated from the _Zeitschrift für das Berg.-Hütten-und Salinenwesen im. preuss. Staate_, 1905, LIII, ii, pp. 219-230. [31] The manufacture of sulphuric acid from these gases has now been undertaken in Silesia on a working scale.—EDITOR. [32] A paper presented before the American Institute of Mining Engineers, July, 1906. [33] _Engineering and Mining Journal_, Sept. 2, 1905. [34] This term is inexact, because the hearths employed in the United States are not strictly “Scotch hearths,” but they are commonly known as such, wherefore my use of the term. [35] Percentages of lead in Missouri practice are based on the wet assay; among the silver-lead smelters of the West the fire assay is still generally employed. [36] This improvement did not originate at either Alton or Collinsville. It had previously been in use at the works of the Missouri Smelting Company at Cheltenham, St. Louis, but the idea originated from the practice of the Picher Lead Company, of Joplin, Mo. [37] This refers especially to the Savelsberg process.