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T H E II M O M E T E R S. 
augcr-lioles on all sides, so as to allow the air to pass 
freely, and firmly luted to its frozen base. To guard 
against the fine and almost impalpable drift, which in¬ 
sinuates itself everywhere, and which would interfere 
with the observation of minute and sudden changes 
of temperature, I placed a series of screens at right 
angles to each other, so as to surround the inner 
chamber. 
The thermometers were suspended within the central 
chamber: a pane of glass permitted the light of our 
lanterns to reach them from a distance, and a lens and 
eye-glass were so fixed as to allow us to observe the 
instruments without coming inside the screens. Their 
sensibility was such that when standing at 40° and 50° 
below zero, the mere approach of the observer caused a 
perceptible rise of the column. One of them, a three- 
feet spirit standard by Taliabue, graduated to 70° 
minus, was of sufficiently extended register to be read 
by rapid inspection to tenths of a degree. The in¬ 
fluence of winds I did not wish absolutely to neutralize; 
but I endeavored to make the exposure to them so 
uniform as to give a relative result for every quarter 
of the compass. We were well supplied with thermo¬ 
meters of all varieties. (30) 
I had devised a wind-gauge to be observed by a tell¬ 
tale below deck; but we found that the condensing 
moisture so froze around it as to clog its motion. 
“September 30, Friday.—We have been terribly 
annoyed by rats. Some days ago, we made a brave 
effort to smoke them out with the vilest imaginable 
