264 ANNUAL OF SCIENTIFIC DISCOVERY. 



bly for the copper it contained, so long ago that now there are forest- 

 trees a foot in diameter growing on the dtbris thrown out then. As 

 zinc was an article not much known at that time, and not in demand, 

 the copper must have been the object. About 10 years ago the 

 United States government, under advice, worked these mines to ob- 

 tain zinc to use in the composition of brass for the construction of the 

 standard weights and measures of the country. The zinc was known 

 to be of such excellent quality, that it was procured without regard to 

 expense for the purposes above mentioned. The ore found in New 

 Jersey comes under the fourth species of Thompson, who calls it 

 " Manganesian Oxide of Zinc," but it has lately been injudiciously 

 proposed to give it a new name after Lord Stirling, who was the 

 original patentee of the district of land where it is found. It was 

 first noticed and analyzed by Dr. Bruce, who found it to contain zinc 

 76, oxygen 16, and oxides of manganese and iron 8 ; but according to 

 Berthier it has oxide of zinc 88, and sesquioxide of manganese 12. 

 Some recent examinations have, as it is said, detected cadmium in this 

 ore. The mineral crops out at the summit of a ridge that is precipi- 

 tous on either side, and about three eighths of a mile in length. The 

 removal of a very slight covering of extraneous material lays open the 

 ores. With this red oxide of zinc is found the mineral called frarik- 

 linite, mingling chemically and mechanically. This franklinite is a 

 species of iron ore which, as found here, yields iron of the finest 

 quality, and fully equal in tenacity and fineness to the Swedish, from 

 which the English manufacture their best steel. It is in veins of from 

 eight to twenty-five feet wide, and lies between two veins of primary 

 limestone, the average depth of which is reckoned by geologists about 

 2,000 feet. Taking the average of the ore, the zinc and iron are near- 

 ly equal in quantity. In some veins the zinc predominates, and in 

 other veins the iron. 



One difficulty, which stood in the way of the reduction of zinc ore, 

 has been overcome by the skill and perseverance of the present own- 

 ers of this Sussex mine ; who, instead of separating the zinc from 

 the iron with which it is combined, by calcination, have recourse to 

 roasting, pounding, and sifting, which has the desired effect : the zinc 

 being reduced by the two former operations to a red powder, and the 

 iron being left in coarser imperfect crystals. 



The zinc, when in this state, is capable of being reduced to an im- 

 palpable powder, and of being used as a paint for fences and out-houses, 

 for which, by its durability and cheapness, it is well calculated. But 

 if it is required to produce the white oxide, it can be readily obtained 

 by calcination, and in this state it promises to supersede the use of 

 white lead as a pigment. But the beauty of the metal alloyed with 

 a very small proportion of tin and lead, is its greatest characteris- 

 tic. Dish-covers, forks, spoons, &c., made of this metal, are second 

 in beauty to nothing but silver, and in this state it retains its lustre 

 in an astonishing manner. A piece of the rolled zinc has been ex- 

 posed to the action of the atmosphere for several months without be- 

 ing tarnished in the least degree. The metal also exhibits great duc- 

 tility and tenacity, and is capable of being drawn to the finest wire and 



