NATIVE CUPPER IODIDE AND OTHER MINERALS. 329 
1. A cavity in gossany carbonate of lead ore has been coated 
with iron and manganese oxides, on which has been implanted 
at irregular intervals, well formed crystals of anglesite, one 
of the largest measuring fully 5 mm. along the edge. 
2. After the complete development of the anglesite, a crystalline 
deposit of copper iodide took place, covering the greater part 
of the floor space between the anglesite crystals. After the 
completion of the copper iodide deposit, a change of conditions 
appears to have occurred, resulting in their partial decompo- 
sition. This change being accompanied by a deposit of 
manganic oxide which has in many instances covered the 
partly altered crystals. 
3. These conditions appear to have been again reversed and a 
second deposit of copper iodide to have been formed upon the 
partly altered and incrusted surfaces of the older crystals. 
These later formed crystals show no signs of decomposition or 
incrustation by other substances, and appear to favour the assump- 
tion that conditions suitable to their development prevailed up to 
the time of their discovery. 
Other Minerals. 
(No. 2) A peculiar mineral not yet satisfactorily classified. At 
first appearance resembles a tangled bunch of cord that had been 
dipped partly in white and partly black paint. Now if you will 
imagine the cord to be changed to impure chalcedony, the white 
paint changed to a fine pearly foliated kaolin-like mineral, the 
black parts being due to penetrating oxide of manganese, you will 
have a very fair idea of the appearance of the specimen and a 
rough outline of its composition. 
Result of preliminary trials— White variety.—B.B. infusible ; 
in borax and phosphor salt gives reaction for silica only ; fused 
with cobalt nitrate yields blue mass. Heated in glass tube (closed) 
gives water, also white fumes condensing as faint sky blue subli- 
mate (not tested). Powder boiled in H,SO, becomes highly 
explosive ; partly decomposed in nitro-hydrochloric acid, more 
