Chap. XXI. 
EXPEEIMENTS. 
417 
per minute^ making 1 pint (16 ounces) in every 24 hours. I then 
cut the branch so much, that during the day it broke; but they 
stni went on at the rate of a drop every 5 seconds, while another 
colony on a branch of the same tree gave a drop every 17 seconds 
only, or at the rate of about 10 ounces 4-|- drams in 24 hours. I 
finally cut off the branch; but tliis was too much for their patience, 
for they immediately decamped, as insects will do from either a 
dead branch or a dead animal, which Indian hunters soon know, 
when they sit down on a recently killed bear. The presence of 
greater moisture in the air increased the power of these distillers: 
the period of greatest activity was in the morning, when the air 
and everything else was charged with dew. 
Having but one day left for experiment, I found again that 
another colony on a branch, denuded in the same way, yielded a 
drop every 2 seconds, or 4 pints 10 ounces in 24 hours, while a 
colony on a branch untouched, yielded a drop every 11 seconds, 
or 16 ounces 2i§ drams in 24 hours. I regretted somewhat the 
want of time to institute another experiment, namely, to cut a 
branch and place it in water, so as to keep it in hfe, and then 
observe if there was any diminution of the quantity of water 
in the vessel. This alone was wanting to make it certain that 
they di^aw water from the atmosphere. I imagine that they have 
some power of wliich we are not aware, besides that nervous 
influence which causes constant motion to om’ own involuntary 
muscles, the power of hfe-long action without fatigue. The reader 
will remember, in connection with this insect, the case of the 
ants already mentioned. 
December —Both myself and men having recovered from 
severe attacks of fever, we left the hospitable residence of Mr. 
Canto with a deep sense of Ins kindness to us aU, and proceeded 
on our way to Ambaca. (Lat. 9° 16' 35" S., long. 15° 23' E.) 
Frequent rains had fallen in October and November, which 
were nearly always accompanied with thunder. Occasionally the 
quantity of moisture in the atmosphere is greatly increased without 
any visible cause: this imparts a sensation of considerable cold, 
though the thermometer exhibits no fall of the mercury. The 
greater humidity in the air, affording a better conducting medium 
for the radiation of heat from the body, is as dangerous as a sudden 
fall of the thermometer: it causes considerable disease among the 
2 E 
