100 A Survey or THE 
Thermometer attached. .78 
Ditto detached: ........68 
Having hung the Barometer up in the tent, and allowed it to acquire 
the temperature of the air and adjusted zero, the following heights we 
observed : 
‘Yhermometer. attached de hk surface of the ve 
Ditto detached 63 CMercury...........20. 8320 
Second reading an hour afterwards, 
Race sees noe 20. 8065 At. Th. 69 
Mereury upper convex surface 
3 2209 DAFCF9 e822 6eBGee% 3 D e ‘o. 7 
Lower part of head of column § : ieee si 
; ? F082 000 0000 cee de OG T4A10 
: Ther. o 
An hour afterwards upper convex .....006...0++.20, 8255 72 
Lower dime vias isacc seis ain't 2 8080 6h 
Afternoon, outside of the tent three hours after filling the tube; 
Whean, at 4 o%clock <s/c'c acu dens no eiv toile nas BOu 7843. 57 
There were very few and. but small (Air) bubbles ‘in the. column, and 
the vacuum was evidently pretty good, as shewn by the smart cracking of 
the mercury against the top of the tube, 
Water boils. ici. o6s dove tibieres’s 196 
WE now begin to boil the mercury in the tube. The tube as 
usual broke. None but a professed artist can expect to succeed in this 
difficult business, once in ten times.— With the unboiled mercury, there 
must be an error, but it should not, 1 think, affect the heights more than _ 
200 feet, and generally not 100 feels and as under the present circum 
slances we cannot de more, we must be content with such approximate 
