45 
A portion of the bitumen was subjected to organic analysis with 
chromate of lead, and gave a mean result as follows : — » 
Carbon, ..... 84' 37 
Hydrogen, ..... 14'89 
Water at 212° Fahr., . . . 00'68 
Inorganic constituents, . . . *06 
10000 
3. Gifnoch Sandstone. 
The third variety submitted to investigation was from Gifnock 
quarry, situated between two or three miles north of Glasgow ; it 
was procured from Mr Napier, chemist, Partick, Glasgow. 
The stone appeared much disintegrated and easily broken. 
The results of the experiments upon this stone, and also upon the 
Partick sandstone, may be seen by referring to the table. 
4, Partick Bridge Sandstone. 
The fourth stone made the subject of experiment was Partick 
Bridge quarry, about a mile and a half due west from Glasgow. 
In the preliminary process of pulverization, preparatory to ana- 
lysis, some, pieces of a black-coloured substance, associated with iron 
pyrites, were found disseminated through the stone, which were 
carefully separated, and made the subject of special inquiry. 
When heated, this substance blackened, due to the presence of a 
small quantity of organic matter ; its solubility in different men- 
strua was ascertained, dilute hydrochloric acid being first added; it 
had, however, little or no action. 
The probability of this substance being clay was suggested to me 
by others ; but from its extreme hardness and general weight the 
supposition did not seem likely. I was led, therefore, to try it by 
fusion with alkaline carbonates. The fused mass was treated, as 
usual, with dilute hydrochloric acid, when a black residue was left, 
which entirely dissolved in more concentrated acid. 
A small portion of this powder was collected and examined; it 
was attracted by the magnet, and its solution in hydrochloric acid 
yielded nothing but iron in the state of protoxide. This circum- 
stance suggested the probability of the supposed clay being, firstly, 
clay very rich in protoxide of iron, or, secondly, entirely an iron 
compound, devoid, or nearly so, of clay ; for, on examining the acid 
solution of the fused mass, nothing but a trace of alumina was dis- 
covered, at once proving the absence of all clay. 
