260 ANNUAL OF SCIENTIFIC DISCOVERY. 



PLATINUM AND DIAMONDS IN CALIFORNIA. 



THE existence of platinum in the gold sands of California has of late 

 been often announced. Specimens from the region have recently been 

 seen by the editors of this Journal. We also learn from a reliable source 

 that the diamond occurs at the placers. Rev. Mr. Lyman, formerly of 

 New England, describes a crystal seen by him, of a straw-yellow color, 

 having the usual convex faces, and about the size of a small pea. He 

 saw the crystal but for a few moments, and had no opportunity for close 

 examination ; but the appearance and form left little doubt that it was a 

 true diamond. Sillimari's Journal. 



NATIVE COPPER OF LAKE SUPERIOR. 



THE size of some of the masses of native copper found in the mines 

 of Lake Superior almost exceeds belief. At the Cliff mine they 

 have been broken up of 60 and even 80 tons in weight. Such pieces 

 are reduced in the mine to fragments of 7 tons or less, and after being 

 hoisted to the surface are still further reduced. The most extraordina- 

 ry mass yet met with has been found at the Minesota mine during 

 the past year. Two shafts have been sunk on the line of the vein, 150 

 feet apart. At the depth of about 30 feet they struck massive copper, 

 which lay in a huge sheet, with the same underlay as that of the vein, 

 about 55 towards the north. Leaving this sheet as a hanging wall, 

 a level was run under it connecting the two shafts. For this whole 

 distance of 150 feet the mass appears to be continuous, and how much 

 farther it goes on the line of the vein either way there is no evidence, 

 nor beside to what depth it penetrates in the solid vein. It formed the 

 whole hanging wall of the level, showing a width of at least eight feet 

 above the floor where its lower edge was lost. In one place, where a 

 partial break afforded a convenient opportunity, it has been cut through, 

 and its thickness found to exceed 5 feet. Assuming the thickness to 

 average only 1 foot, there would be in this mass 1,200 cubic feet, or 

 about 250 tons. 



The mode adopted to remove the*se masses is to cut channels 

 through them with cold-chisels, after they are shattered by large 

 sand-blasts put in behind them. Grooves are cut with the chisels 

 across their smallest places, one man holding, and another striking, 

 as in drilling. A chip of copper three fourths of an inch wide, and 

 up to six inches in length, is taken out, and the process is repeated until 

 the groove passes through the mass. The expense of this work 

 is from $8 to $12 per superficial foot of the face exposed. Frag- 

 ments of vein-stone inclosed in the copper prevent the use of saws. 

 A powerful machine, occupying little room, is much needed, which 

 would perform more economically this work. The greatest thickness 

 of any mass cut through at the Cliff mine has been about 3 feet. 

 Their occurrence through the vein is not regular. Barren spots alter- 

 nate with productive portions. The same is the case in all the mines. 

 The total product of the Cliff mine for the year 1848 is estimated at 

 830 tons, averaging 60 per cent. The product of the year 1849, it is 



