230 



MERCURY 



year 1853 the total exports from San Francisco amounted to 1,350,000 Ibs., valued at 

 683,189 dollars. All this, together with" the large amount used in California, was the 

 product of the New Almaden mine in the Santa Clara county, 12 miles from the town 

 of San Jose, which is 54 miles from the city of San Francisco. The working of the 

 mine was begun in the year 1846-7 by an English company, but for some reasons 

 was not profitable ; in 1849-50 it fell into American hands. 



The analysis compared with that of the Old Almaden ore furnished the following 

 results to Mr. Bealey (' Quarterly Journal of Chemical Society,' vol. iv.) : 



Mercury 



Sulphur 



Iron . 



Lime 



Alumina 



Magnesia 



Silica 



Loss. 



New Almaden 



. 60-90 



. 11-29 



. 1-23 



1-40 



. 0-61 



. 0-49 



. 14-41 



67 



Old Almaden 

 3779 

 16-22 

 10-36 

 35*12 silica and alumina. 



51 



100-00 100-00 



Production of Quicksilver in California. 



Metallurgy of Quicksilver. The metallurgic treatment of the quicksilver ores is 

 tolerably simple. In general, when the sulphuret of mercury, the most common ore, 

 has been pulverised, and sometimes washed, it is introduced into retorts of cast iron, 

 sheet iron, or even stoneware, in mixture with an equal weight of quicklime. These 

 retorts are arranged in various ways. 



Prior to the 17th century, the method called per descensum was the only one in use 

 for distilling mercury ; and it was effected by means of two earthen pots adjusted 

 over each other. The upper pot, filled with ore, and closed at the top, was covered 

 over with burning fuel ; and the mercurial vapours expelled by the heat, passed down 

 through small holes at the bottom of the pot, to be condensed in another vessel placed 

 below. However convenient this apparatus might be, on account of the facility of 

 transporting it, wherever the ore was found, its inefficiency and the losses it occa- 

 sioned were eventually recognised. Hence, before 1635, some smelting works of 

 the Palatinate, had given up the method per descensum, which was, however, still 

 retained in Idria ; and they substituted for it the furnaces called galleries. At first 

 earthenware retorts were employed in these furnaces ; but they were soon succeeded 

 by iron retorts. In the Palatinate this mode of operating is still in use. At Idria, 

 in the year 1750, a great distillatory apparatus was established for the treatment 

 of the mercurial ores, in imitation of those which previously existed at Almadeu, 

 in Spain, and called aludel- furnaces. But, since 1794, these aludols have been 

 suppressed, and new distillatory apparatus have been constructed at Idria, remark- 

 able only for their magnitude ; exceeding, in this respect, every other metallurgic 

 erection. 



There exist, therefore, three kinds of apparatus for the 

 distillation of mercury: 1, the furnace called a gallery ; 

 2, the furnace with aludels ; and 3, the large apparatus 

 of Idria. Wo shall describe each of these briefly, in suc- 

 cession. 



1. Furnace catted Gallery of the Palatinate. The con- 

 struction of this furnace is disposed so as to contain four 

 ranges, a a 1 , b b', of largo retorts, styled cucurbits, of cast 

 iron, in which the ore of mercury is subjected to distilla- 

 tion. This arrangement is shown in fig. 1432, which 

 presents a vertical section in the line a b of the ground plan, fig. 1433. In tho 

 ground plan, tho roof ce, of tho furnace (fig. 1432) is supposed to be lifted off, 



