80 Sir WILLIAM HAMILTON’S Account of 
The fhell or outward coat of the bombs that burft, 
and of which we found feveral pieces, was always com- 
pofed of frefh lava, in which many fplinters of the more 
ancient lava that had been inclofed are feen flicking. I 
was much pleafed with this difcovery, having been 
greatly puzzled for an explanation of this volcanic ope- 
ration, which was new to me, and which was very fre- 
quent during the eruption of the 9th of Auguft. 
The phenomenon of the natural fpun-glafs, which 
tell at Ottaiano with the allies on the 5th of Auguft, was 
likewife clearly explained to me here. I have already 
mentioned, that the lava thrown up by this eruption was 
in general more perfectly vitrified than that of any for- 
mer eruption, which appeared plainly upon a nearer 
examination of the fragments of frefh lava, the pores of 
which we generally found full of a pure vitrification, 
and the f cor ice themfelves, upon a clofe examination with a 
magnifying glafs, appeared like a confufed heap of fila- 
ments of a foul vitrification. When a piece of the folid 
frefh lava had been cracked in its fall without feparating 
entirely, we always faw capillary fibres of perfect glafs, 
reaching from fide to fide within the cracks. If I may 
be allowed a mean comparifon, which, however, conveys 
the idea of what I wifli to explain better than any other 
I can think of, this lava refembled a rich Parmefan 
cheefe, 
