188 Scienti/ic Intelligence. — Zoology^ 



burgh ; the Uact is about 230 yards wide, by an average length 

 joi upwards of 900 yards. The metaUiferous veins consist a£ 

 iiard quartzoze rock between walls of decomposed talcose slate. 

 A portion of loose red soil, by washing two handfuls of it, gave 

 a considerable quantity of minute granular gold, and similar re- 

 sults were obtained by washings in other places. A principal 

 aufiferous quartz vein is from 2 feet 6 inches to 3 feet 6 inches 

 wide; it stands vertically between walls of talcose slate; there 

 is also, on either side, a vertical bed of auriferous red earth, from 

 2 to 3 feet wide, and bounded also by talcose slate. The auri- 

 ferous quartz vein has been exposed to view for 637 feet, with 

 A width of 30 inches, and it would appear that this is only the 

 beginning. By a rough process of washing, amalgamation and 

 evaporation of the mercury, three and half grains of gold were 

 obtained from four pounds of the ore, taken indiscriminately 

 from all parts of the vein, and in another experiment five grains 

 of gold were produced from four pounds of pure milk-white 

 quartz, which had no appearance or indication of containing any 

 tnetal at all, Messrs Del Rio and Millington think tliat each 

 pound of the ore may be made to yield one grain of gold, or 5 

 pennyweights to the 100 pounds of ore ; this would much niort; 

 -than pay the expense, which cannot exceed one dollar on 100 

 Jb. of the crude material. Xt appears, that by heating tlie 

 quartz red hot, and throwing it into cold water, 8 grains of gold 

 were obtained from 5 pounds of ore. In the opinion of Mr 

 Dickson, the Rappahannock mines perfectly resemble all the 

 others in Virginia. -On the whole, the gold region of the United 

 States is very extensive, rich and promising, and there is every 

 4idventitious advantage of fuel, food, climate, cultivation and 

 security. {We Ixave seen a decisive experiment of this kii^ 

 upon white quartz from Virginia, which yielded a considerable 

 •quantity of gold by simple pounding and washing without amal- 

 gamation. — Ed.] — Slllimans Journal. 



S. On Aphis Perskce. — M. Morren has presented to tbe 

 Academic Royal de Sciences of Brussels, the second part of his 

 memoir on the flight, in 1834, of the Aphis persicce. He recalls 

 to recollection that, during the autumn of 1834, various towns 



