422 Mr, Greville on the 
“ contains iron ; it is of a dull lustre, difficult to work, because 
“ it resists fire long. It is found at Potosi, at Chocaya, and 
“ other places, with the minerals negrillos and rosicleres.” 
Having mentioned the varieties of crystallized and amorphous 
Corundum, and the miscellaneous facts relative to my collec- 
tion of that substance from India and China, it might be suf- 
ficient to give an icon of the crystal, and close a paper already 
prolix ; but, having with satisfaction observed, within the last 
years, the science of mineralogy gaining ground in Great Bri- 
tain, from the knowledge acquired by several gentlemen who 
have examined the mines, and formed personal acquaintance 
with the most experienced and learned men on the Continent, 
and also from ingenious foreigners, who have communicated 
their observations on English fossils, and connected them with 
the most approved systems, it may perhaps be accepted as a 
sufficient apology for what follows, that I consider it as a desi- 
deratum to English mineralogists, to be invited to a preference 
of permanent characters, which the study of crystallization has 
collected, and which promises to be a certain method of ascer- 
taining the laws by which elective attraction arranges and 
combines molecules of matter. 
It is true, the progress of crystallography has been extremely 
slow, and different nations have contributed to its present 
improvement. It is rather remarkable, that the earliest trea- 
tise on metallurgy, of authority, was published in Italy, by 
Vanoccius Biringuccius, just before Agricola published 
his treatise in 1 546 in Germany ; and the first treatise on the 
structure of crystals I know, is also from Italy, by Nicolas 
Steno, Prodromus Dissert ationis de Solido intra Solidum na- 
turaliter contento. Florentine , 1 66 g, in 4to. A work of great 
