[1749] The substance here mentioned, though its name is the foundation of our word “arsenic,” is not the arsenic of modern commerce, but probably a sulphuret of arsenic containing a less proportion of sulphur than the Sandarach of the last Chapter.—B.
[1750] The other two mentioned species naturally divide into laminæ, while this kind is disposed to separate into fine fibres.—B.
[1751] By this process a considerable portion of the sulphur is expelled, so as to cause the orpiment to approximate to the state of arsenic.—B.
[1752] See end of B. ii.
[1753] See end of B. ii.
[1754] See end of B. iii.
[1755] See end of B. ii.
[1756] See end of B. ii.
[1757] A different person from the Messala mentioned at the end of B. ix. He is mentioned in B. xxxiii. c. [14], B. xxxv. c. [2], and in Chapter [38] of this Book; but nothing further seems to be known of him.
[1758] See end of B. vii. and Note 1315 to B. vii. c. 53.