and Qtiick-lime upon heated Galena. i "^'^ 



b. Six inches of the mkltlle of the tube was quite empty, ex- 

 cepting a small number of brilliant cubical crystals, which 

 seemed to be a portion of sublimed galena. 



c. Three inches of the end of the tube connected with the 

 trough was nearly filled with sublimed galena, beautifully cry- 

 stallized in cubes of considerable size, and having a very 

 splendid appearance. These crystals broke again into other 

 cubical fragments having very brilliant faces, and in this re- 

 spect exactly resembled the original ore before being subjected 

 to heat. A small quantity of ore was deposited in the coldest 

 part of the tube, near the end projecting from the furnace, in 

 the form of a fine blueish-gray powder without cohesion. Not 

 a particle of true metallic lead was produced by the operation. 



Experiinent 2. — Another tube was coated and arranged ex- 

 actly as in the last experiment. Nine inches of the portion 

 nearest the trough were filled with pieces of recently burnt 

 lime, each about the size of a pea; and when heated to white- 

 ness, 600 grains of galena were introduced into the end of the 

 tube to which the retort was attached ; and after being suffi- 

 ciently heated, it was carried through the highly incandescent 

 lime in the state of vapour, by a cun-ent of steam. During the 

 process a large quantity of sulphuretted hydrogen gas was 

 given off, but the water in the trough never became so milky 

 as in the last experiment. 



On opening the tube at the end of the operation its ap- 

 pearance was as below. 



d. All the galena was expelled from the end into which it 

 was introduced, no portion whatever remaining. 



e. The lime in the middle of tiie tube exhibited the same 

 appearance as when introduced, excepting one or two pieces 

 which had acquired a yellow colour on the surface; but this 

 yellow colour did not penetrate to any depth; and if occa- 

 sioned by the formation of sulphuret of lime, its quantity must 

 have been very inconsiderable. 



f. A few pieces of lime towards the end of the tube had ap- 

 parently imbibed a portion of galena ; as they had acquired 

 weigiit considerably, and exhibited a steel-grained fracture 

 when broken. Tlie colour of these pieces on the outside was 

 a fine dark indigo blue. 



^. Towards the extremity of the heated part of the tube, a 

 ([ilantity of tiie ore operate! upon was deposited in a crystal- 

 line lorm as before ; but its colour was externally a very dark 

 intligo blue, diilL-ring in this respect from that deposited in the 

 first experiment. 



//. A <|uantily of ore was found in the form of a grayish 

 black powder as before, near the end of the tube. 



/'. Some 



