182 BULLETIN OF THE ESSEX INSTITUTE. 



Institute of Technology (Proc. Boston Soc. Nat. History, 

 Yol. xvn, pp. 200-204), gives : silver, $1,422. per ton ; 

 gold, $145.12 per ton and 27 per cent of copper. The 

 galena (30 pounds) from the Chiprnan mine analyzed by 

 Prof. Richards, yielded 25 lbs. of refined lead, 436.32 

 grains of silver and 4.19 grains of gold. An analysis of 

 this galena made by myself at the Lawrence Scientific 

 School gave silver at the rate of 27 ounces per ton. 



Thus it is seen that gold, silver, lead and copper occur 

 in Essex County. The gray copper of the quality above 

 indicated is very rare even in Newbury and I do not be- 

 lieve that it is to be f ound in the county in sufficient quan- 

 tities to be mined at a profit. 

 No. 2. Graphite. 



This occurs in minute foliated scales in the granitic 

 rocks of Peabody and Danvers, and in the slaty, carbon- 

 iferous shales of Topsfield, Middleton and Lynnfield 

 Centre. 

 No. 3. Stibnite : Gray Antimony. 



Found associated with galena at the Newbury and New- 

 bury port silver rnines. 

 No. 4. Molybdenite. 



Found in foliated niasses of considerable size at the 

 Pomeroy granite quarry at Gloucester, in the augite- 

 syenite at Salem Neck and some good specimens have 

 been found in the diorite at Marblehead. 

 No. 5. Silver Ore. 



Newbury, Newburport, Aniesbury, Rowley, Boxford 

 and Lynnfield Centre. 

 No. 6. Galena: Lead Ore. 



Found in the same places as the last named. 

 No. 7. Bornite : Variegated Copper Ore. 



Luther Noyes copper mine and the southern part of 

 Kent's Island, Newbury. 

 No. 8. Chalcopyrites : Copper Pyrites. 



