on certain stony and metalline Substances , &c. 185 
colour, slightly inclining to green ; and Its hardness was rather 
inferior to that of calcareous spar. The quantity of it, however, 
was too small to be submitted to such an investigation as might 
have determined its nature. The black criist which covered 
the stone, was rather thinner than that of the stones already 
described ; and seemed to have undergone a kind of contraction, 
which had produced in it a number of fissures or furrows, 
thereby tracing upon the surface the appearance of compart- 
ments, similar in some measure to what is observed in the stones 
called Septaria, 
The specific gravity of this stone was 34,18. 
STONE FROM BOHEMIA. 
The internal structure of this stone is very similar to that of 
the stone from Yorkshire. Its grain is finer than that of the 
stones from Benares : in it may be observed the same gray sub- 
stance, both in small globules and in particles of an irregular 
shape; also the same particles of metallic iron. The same kind 
of earthy substance likewise served to connect the other parts 
together. 
This stone, however, differs materially from the others. 
F irst. The particles of pyrites cannot be seen without a lens. 
Secondly. It contains a much larger quantity of iron in the 
metallic state; insomuch, that the proportion of that metal, 
separated from it by means of the magnet, amounted to about 
of the weight of the whole. 
This stone has also (owing perhaps to its having remained a 
much longer time in the earth than the preceding ones, all of 
which were taken up nearly at the very instant of their fall,) 
another difference, viz. many of the particles of iron in a 
mdcccil B b 
