on the Newry pitch-stone , &c. 327 
retort being thinner than the rest had fused, but fortunately 
not until the whole of the bitumen had come over. The 
residuum was again a pumice, exactly the same as in the ex- 
periments with the iron retort. 
Experiment 3. 
Slaty compact pitch-stone. 
A green glass retort was again charged with the pitch-stone 
which I had been analysing, namely, the slaty compact ; but 
the neck of the retort, being thinner than the body, fused. On 
examining the mass within the retort, a light-coloured pumice 
was found at the bottom, and a dark one at the top. 
Experiment 4. 
100 grains of the slaty compact pitch-stone which I had 
been analysing, lost by ignition 8,0 per cent. : when fused it 
lost 0,5 more, and formed a light ash-grey glass. 
Experiment 5. 
480 grains of the same were distilled after the water was 
expelled by ignition, and therefore the danger of decompo- 
sition removed, in an iron retort. Bitumen came over, and 
the process appearing to be completed the receiver was re- 
moved, after which some more bitumen dropped from the 
retort. The bitumen in the receiver smelt more of naptha 
than the former products, but that which dropped had the 
same smell of tobacco. What w&s condensed in the receiver 
was very volatile, being driven from one end of the phial to 
the other, namely, by the heat of the hand. The contents of 
the retort were a light pumice, as before. 
