ELECTRICITY 455 
The ill success of these experiments seems to me to 
have arisen chiefly from the uncommon dampness of the 
circumambient air, which had been observed by everybody 
since we crossed the tropic, and is fully noticed in my 
journal. By this solution alone can all the phenomena 
that appeared be accounted for. 
Air charged with particles of damp is well known to be 
of all others the greatest enemy to electricity. It im- 
mediately attracts and dissipates all the electrical matter 
which is collected by the machine, which therefore worked 
faintly for a little while, till the damp was condensed on 
the conductor, and chiefly on the surface of the glass phial, 
and then ceased entirely. A small quantity was, however, 
always noticeable upon the surface of the plate, even to the 
end of the conductor. 
The phial, though charged as full as the machine would 
fill it, even at the time of its best working, scarcely retained 
the electrical matter at all, owing doubtless to the com- 
munication made by the condensed damp between the 
coating and the stopper of the phial; this increased every 
moment, so that at last it would not contain any electricity. 
The situation on board ship would not allow the use of 
a fire to warm the whole machine, which should have been 
done, and which would have been a great satisfaction, but 
the motion of the ship, the distance of the galley from the 
cabin, and the number of people who are constantly busy 
there, made that impossible. 
The dampness of the air complained of here has not 
been observed now for the first time. Piso, in his account 
of the Brazils, mentioned it, and says that victuals which 
have kept well before spoil immediately there. This there- 
fore may account for the general opinion of electrical 
machines failing to work when near the line, as the fault 
could not be in my machine which worked remarkably well 
in London, and fully as well as I expected in Madeira. 
25th October 1768, 17 miles south of the line—WMr. 
Green’s machine. This was made by Watkins: the jar 
was of glass 8 inches high and 7-deep, coated with 
