188 Scientific Intelligence. — Zoology^ 



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

 of upwards of 900 yards. The metalliferous veins consist of 

 bard 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 

 auriferous 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 

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

 ferous quartz vein has been exposed to view for 627 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 

 metal at all. Messrs Del Rio and Milling-ton think that 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 more 

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

 lb. of the crude material. Jt appears, that by healing the 

 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 ail the 

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

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

 adventitious advantage of fuel, food., climate, cultivation and 

 security. [We have seen a decisive experiment of this kind 

 upon white quartz from Virginia, which yielded a considerable 

 quantity of gold by simple pounding and washing without amal- 

 gamation . — E d.J — S Human's J ournaL 



zoology. 



B. On Aphis Persicce. — M. Morren has presented to the 

 Academie 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 



