20 ENGLAND TO RIO DE JANEIRO CHAP. I 
see the different faces that were made on this occasion, some 
grinning and exulting in their hardiness, whilst others were 
almost suffocated, and came up ready enough to have com- 
pounded after the first or second duck, had such a proceeding 
been allowable. 
Almost immediately after crossing the tropic the air had 
sensibly become much damper than usual, though not 
materially hotter: the thermometer in general stood from 
80° to 82°. The nearer we approached to the calms, the 
damper everything grew; this was very perceptible even to 
the human body, but more remarkable was its effect upon 
all kinds of furniture. Everything made of iron rusted so 
fast that the knives in people’s pockets became almost use- 
less, and the razors in cases did not escape; all kinds of 
leather became mouldy, portfolios and trunks covered with 
black leather were almost white. Soon afterwards this 
mould adhered to almost everything; all the books in my 
library became mouldy, so that they had to be wiped to 
preserve them. 
About this time we came into the calms, which we met 
with earlier than usual: the thermometer was then at 83°, 
and we suffered from the heat and damp together. Bathing, 
however, kept me in perfect health, although many of the 
ship’s company were ill of bilious complaints, which, how- 
ever, were but of short duration. This continued till we 
got the S.E. trade, when the air became cooler, but the 
dampness continued yet: to that I chiefly attribute the ill- 
suecess of the electrical experiments, of which I have written 
an account in separate papers, that the different experiments 
may appear at one view." 
The air, during the whole time since we crossed the 
tropic, and indeed for some time before, has been nearly of 
the same temperature throughout the twenty-four hours, the 
thermometer seldom rising more than a degree during the 
time the sun is above the horizon; the cabin windows have 
been open without once being shut ever since we left Madeira. 
29th. This evening the sea appeared uncommonly beautiful, 
1 An account of these will be found at the end of the volume. 
