so 
notTBX-STONB. 
Component 
parts of 
rotten-stone. 
Analytical 
results. 
in mineral compositions*, we must first recur, it is evident, to 
the nature of the constituent matter of the original rock, as i 
well as of the substance, which the disintegration of such rock I 
has been presumed to produce. 
Limestones, it is well known, are composed principally of an | 
indurated calcareous carbonate ; — Rotten-stone, according to i 
the following analyses, of alamine in a loose or earthly form, 
and with its constituent particles in a very minute state of 
division — But we must remember, that many other principles 
enter into- the composition of most limestones besides carbo- 
nate of lime ; as alumine, silex, bitumen, and sometimes 
biagnesia ; — and that Rotten-stone contains, besides alumine, 
silex, bitumen, or carbon, and frequently iron and calcareous 
earth j — and that the comparative proportions of these com- | 
ponent parts diS'er greatly in the difterent varieties both of I 
limestone and rotten-stone. : 
Our analasis of rotten-stone has afforded the following 
results. 
1. Very hard Rotten-istone , approaching Black Limestone iit I 
external appearance. | 
Alumine 74 
Silex 3 
Carbonate of Lime 14 
Oxide of Iron. . 2 
Inflammable matter and loss 7 
, 100 
2. Another specimen of the hard variety, hut of a light hrown 
colour, 
Alumine 80 
Silex 2 
Carbonate of Lime lO 
Oxide of Iron i 
Inflammable matter and loss 7 
100 
* Transimitation of silex into lime, or that of lime into silex or 
alumine, however strongly contended for by some modern Geologists, 1 
most assuredly ought not to be assumed in any attempt to account for ' 
the phenomena of the mineral kingdom, till supported by stronger facts 
than those on which it rests at present. 
3. Hard j 
