246 
DR. DAVY’S ACCOUNT OF A NEW VOLCANO 
No 4, about three miles from Cape Bianco, in the neighbourhood of Girgenti. 
No. 5, between Girgenti and Gozo, in lat. 36° 33', long. 13° 31'. And No. 6, 
about a mile off Gozo. I ascertained their specific gravity with great care, by 
means of a delicate balance of Robinson’s, and found it the same in each in¬ 
stance, viz. 1-0287, water at 73° Fahr. being rOOOO, which is about the ave¬ 
rage specific gravity of the surface water of the open parts of the Mediterranean 
in the summer season *. I ascertained also with care, the saline residue which 
each specimen afforded, evaporated over boiling water and exposed to this tem¬ 
perature as long as any loss was sustained. The evaporation was made in a 
silver capsule, which was weighed as speedily as possible and whilst still warm. 
The residue per cent, of each was as follows : 
No. 1 
2 
3 
4 
5 
6 
4-46 
4-43 
4*40 
4*39 
4*43 
4*33 
Even these slight differences of the quantity of saline residue might have been, 
and probably were owing to the circumstances of manipulation, and the state 
of the atmosphere in relation to humidity when the experiments were made. 
In all of them were discoverable a slight trace of sulphur and an extremely 
minute quantity of iodine. The apparent absence of the latter substance in 
the water of the crater, might either have been owing to the high temperature 
to which it had been exposed, and to which its superior specific gravity is to 
be attributed, or to the presence of the hyposulphites, which perhaps might 
have masked such a very minute quantity, if present. 
I have now mentioned all the products of the volcano that have come to my 
knowledge, excepting the gaseous. The specimens of gas (two in number) 
which I received from Captain Wodehouse were in the wine-bottles in which 
they had been collected. One was full of air; the other contained about four 
fifths air and one fifth turbid water of the volcano. They had merely been 
* In bays in which no rivers empty themselves, I have found the specific gravity of the water higher ; 
and towards the embouchures of great rivers lower, as in the Adriatic and the Hellespont. 
