AMERICAN INSTITUTE. 557 



Professor Mason introduced the subject of tlie evening, " Zinc,'* which 

 was continued from last evening, by remarking that the " bag process," 

 has produced seven thousand tons of "zinc-white" in the past year ; that 

 zinc-white and zinc ores are now regular articles of export, and that the 

 mines at Sterling, and at Bethlehem can produce more zinc-white than is 

 now produced in the world, at prices which must find a market, and drive 

 the poisonous white-lead out of use in all civilized countries. 



Col Curtis described the bag process as follows : The zinc ore is crushed 

 fine and mixed with coal-dust, after which the mixture is placed in a zinc 

 furnace, about the size of a common dutch stove. Heat being applied, the 

 zinc rises in vapor, passes through the flue, and is caught in a " bag" at 

 top, from which it is afterward collected in the form of a snow-white 

 powder. This is formed directly from the ore. 



Mr. Seeley gave an analysis of the lemon-colored oxyd of zinc belonging 

 to the Jersey Company, which showed that the impurities were iron and 

 manganese. There is no metal more easily reduced than zinc. The 

 apparatus should be a retort with a wide cupola, for the zinc is driven off 

 at a read heat in the metallic state, if no oxygen be present ; but if oxygen 

 be present, the zinc will be converted into a white oxyd, which is some- 

 times called "philosopher's wool." Ked oxyd predominates as an ore in 

 New York. 



Mr. Churchill gave some account of the localities in England where zinc 

 is found. In Somersetshire, England, near Wells and Bristol, there is a 

 limestone range 800 feet above the level of the sea. This contains four 

 kinds of metal ; an ore of zinc, one of lead, mercury, and iron. In the 

 time of Elizabeth, the poor were allowed to work the minerals in this dis- 

 trict which was included in the Royal Forest ; and so unimportant was 

 zinc esteemed that no royalty was levied upon it. 



Professor Mason. — Zinc was taxed by Pitt, so that he ascertained 

 exactly the produce in England in his day, and that was greater than at 

 any time since. England has got her zinc principally from Silesia ; now 

 she begins to get it from this country. 



Mr. Curtiss. — In Ure's Dictionary, a "bag process" for collecting lamp- 

 black is described, but in that process the bag is open ; in the other case 

 the bag is closed. 



Mr. Churchill. — Long flues are used in England for collecting zinc. 



Professor Mason. — There are three points in the "bag process." 1st. 

 The bag is tied up. 2d. A blower is used to create an artificial current of 

 air through the furnace. 3d. The furnace is made so as to be fed with 

 fuel and ore from the top. It may be well to remark, that the lowest 

 price at which the English East India Company sold zinc was thirty cents 

 a pound. 



Dr. Stevens, — America can and will furnish zinc and all other metals in 

 sufiicient abundance for the world, because our geological and mineralogi- 

 cal formations are developed on a grander-scale than in any other part of 



