224 J. K. Creighton — On "Figotite" in Cormvall. 



between Porthcurnow and Porthchapel, I was impelled to make a 

 searcli for the mineral. Last July I succeeded in finding a cave 

 near Porthcurnow, the small opening into which was partially 

 hidden by masses of fallen rock ; here I found after a rough 

 examination traces of the mineral for which I was looking. In 

 the course of the next few days I made a complete survey of the 

 cave, which is about 75 feet long and 15 feet wide, and varies from 

 10 to 15 feet in height. At some distance from the opening is 

 a large block, which permits only little light to reach the farther 

 end of the cave ; the greater part of the block is covered with a 



crust, varying from 1 to 15 lines in thickness, of the mineral in 

 question ; the crust had apparently been a result of the continuous 

 drip of water from that part of the roof which is immediately 

 above. Other crusts found at the farther end of the cave were 

 from 10 to 30 lines in thickness. As the nature of the mineral 

 was not known to anyone in the neighbourhood, I sent a fragment 

 to the Natural History Museum at South Kensington, where it was 

 examined by Mr. Fletcher. He sent me the following information : — 

 " The dark brown fragment is opaque in the mass, but transmits 

 light of a rich red colour through its thinner edges ; it has the lustre, 

 fracture, brittleness, low specific gravity, and indeed the general 

 aspect, of an ordinary resin; to one's surprise, however, a flake 

 held in a gas-flame refuses to burn. Heated on a platinum lid 

 to a red heat, a fragment slowly burns away, and, after final 

 heating with the blowpipe, leaves a grey ash ; heated in a glass-tube 

 open at only one end a fragment gives off much water and empy- 

 reumatic products, and leaves a black mass behind. The powdered 

 mineral is of a yellow colour. These characters and behaviour 

 indicate that the substance you have sent me is identical with a 

 mineral described before the Royal Society more than fifty years 

 ago by Mr. James F. W. Johnston, M.A., F.E.S., and named by 

 him Pigotite after the Eev. M. Pigot, the co-discoverer." 



Mr. Fletcher at the same time sent me a copy of Mr. Johnston's 

 paper, from which I find that the resin, " which had been found 

 as an incrustation on the sides of certain caves occurring in the 

 granitic cliffs on the east and west coast of Cornwall," was regarded 

 as a chemical compound of alumina, a new organic acid (mudesous 

 acid) and water. As regards its mode of origin Mr. Johnston says 



