METALS AND THEIR ORES. 49 



Considerable work has been done upon this projoerty since 1840. The 

 tremolite does not occur with the copper at great depths. Latterly the 

 zinc predominates, and there is a little galena. At the time of my visit 

 the mine was full of water, and I could learn little in addition to what 

 has been presented. I made the following statements respecting it in 

 1869: 



The Warren zinc mine is now under the management of Capt. Edgar. It has been 

 known for twenty 3'ears as a copper mine, but as the vein has been followed down- 

 wards the zinc has to a considerable extent increased at the expense of the copper, 

 and it is for the zinc chiefly that the mine is now wrought. The principal vein is of 

 quartz, ten feet wide, crossed by a mass of the mineral tremolite. The hanging wall 

 is a sandstone, the foot wall micaceous slate. To the depth of twenty-five feet, copper 

 ore and galena predominated. Below that point, to the bottom of the excavation, one 

 hundred and fifty feet, the zinc is the most abundant, amounting to one half. At the 

 bottom the vein is twenty feet wide, and there is a drift one hundred and eighty feet 

 in length. There seems to be a "pipe " or " chimney'' of pure ore in the vein, some- 

 times fifteen feet thick and twenty broad, which is the most valuable part of the me- 

 tallic sheet. It does not proceed on the direct line of the dip, but passes down about 

 tap degrees from it. 



At present (1869) the ore is first sent to the Lowell Bleachery Company, Mass., 

 where the sulphur is removed and converted into sulphuric acid. The residue then 

 goes to Bethlehem, Pa., where it is smelted into spelter. 



Since 1870 the mine has not been worked. It is owned by Horace 

 Brooks, of Franconia. 



Copper Mines in Southern New Hampshire. 



Within a few years a new impulse has been given to mining for pyrites, 

 on account of the sulphur contained in it, for the manufacture of sul- 

 phuric acid. This is used in bleaching, fabrication of artificial fertilizers, 

 and a hundred other ways. Quite recently, chemical works for the util- 

 ization of sulphur have been established about the principal cities, and 

 there is a great call for the ores containing sulphur. By the burning of 

 the ore, — a sulphuret of iron, — the sidphur takes oxygen from the air, 

 becoming sulphurous acid. This is condensed in water in leaden cham- 

 bers, where an additional atom of oxygen is added, and the resulting 

 compound is sulphuric acid. One of the principal sources of this pyrites 

 VOL. v. 7 



