on a mineral Production from Devonshire . 157 
leaving any notable residuum ; but a small part remains un- 
dissolved, when coloured or opaque specimens are exposed to 
the alkaline lixivia. 
A small semi-transparent piece, acted on by the highest 
heat of an excellent forge, had its crystalline texture destroy- 
ed, and was rendered opaque ; but it did not enter into fusion. 
After the experiment it adhered strongly to the tongue, and 
was found to have lost more than a fourth of its weight. Water 
and alcohol, whether hot or cold, had no effect on the fossil. 
When it was acted on by a heat of from 212 0 to 6oo° Fahren- 
heit in a glass tube, it gave out an elastic vapour, which when 
condensed appeared as a clear fluid possessing a slight em- 
pyreumatic smell, but no taste different from that of pure 
water. 
The solution of the fossil in sulphuric acid, when evaporated 
sufficiently, deposited crystals which appeared in thin plates, 
and had all the properties of sulphate of alumine ; and the 
solid matter, when redissolved and mixed with a little carbo- 
nate of potash, slowly deposited octahedral crystals of alum. 
The solid matter precipitated from the solution of the white 
and semi-transparent fossil in muriatic acid, was in no manner 
acted upon by solution of carbonate of ammonia, and therefore 
it could not contain any glucine or ittria ; and its perfect 
solubility without residuum in alkaline lixivia shewed that it 
was alumine. 
When the opaque varieties of the fossil were fully ex- 
posed to the agency of alkaline lixivia, the residuum never 
amounted to more than one-twentieth part of the weight of 
the whole. In the white opaque variety, it was merely calca- 
reous earth, for when dissolved in muriatic acid, not in excess, 
