192 Scientific Iittelfi(jence — Mineralo(ji/. 



MINERALOGY. 



3. Copper of the Lake Superior Region. — {From a recent letter 

 by C. T. Jackson.) — The native copper mines of this region are 

 truly wonderful, both for the quantities that are exposed in the 

 mines, and the magnitude of the masses of native metal. Truly they 

 are copper veins. I have seen the most noble lumps in this place, 

 and one has lately been blown off in stopping the ClifF mine, Eagle 

 River, that will weigh 50 tons. It is now cutting up into pieces of 

 two or three tons weight, so that it may be sent to market. The 

 supply furnished by that mine is as regular as it is in most mines 

 furnishing ore. This spring the miners had 400 tons on hand, and 

 they have sent down to Baltimore 600 tons at this time ; and they 

 estimate the amount of copper that they will ship at from 900 to 

 1000 tons before the close of navigation in November next. This 

 mine has been wrought with proper energy, and will richly repay the 

 owners. There are several other native copper mines here that are 

 equally promising, and will produce well when wrought with proper 

 energy and skill. 



Copper Falls mine is an example, and is doing well. The north- 

 west is another full of promise, and I have seen others which look 

 very rich, but which are not yet opened deep enough to exhibit their 

 contents. The shafts at the ClifF mine are 205 feet deep, and the 

 hill above shews the vein in the face 213 feet higher, so that we 

 know that the copper extends at least 418 feet. Those who were 

 surprised that I recommended working mines for native copper, 

 should come and see, and they would believe. The case is indeed a 

 new one, and we watch with interest the results. 



Native Silver is found mostly at and near the junction of the trap 

 and sandstone where the veins end, not passing into the sandstone. 

 — {American Journal of Science and Arts, vol. vii., Second Series, 

 March 1849, p. 286.) 



4. Native Silver in Norway. — It is reported in the Swedish 

 official paper of the 27th October, that at the King's mine, at 

 Kongsberg, two lumps of native silver, severally 238 and 436 pounds, 

 wei'e obtained within the preceding two months. This mine was of- 

 fered for sale in London twenty years ago for £10,000, but failed of 

 purchasers. It now brings to the Government more than this sum 

 annually. 



5. The Arkansite, according to the examination of Mr Whitney, 

 is pure titanic acid, with only a trace of iron (and not a niobate, as 

 inferred by Professor Shephard), and has the crystalline form and 

 specific gravity of Erookite. His trials make the specific gravity 

 4*085. Its insolubility in acids is strong presumptive proof that it 

 is not titanic acid in combination with a base, since ail the known 

 titanates are soluble in acids. — {American Journal of Science and 

 Arts, vol. vii., No. 21, p. 433. 



