i 311 | 8L1 | 311 a 
2 5 | 43.8 |- 428 |.39.0 | -48 3.8 
3 | 10 | 665 | 536 | 491.) 74 4.5 
4 | 18 |-636 |.60.0 | 562 | 74 3.8 
5 | 27 | 67.8 | 644 | 622 | 56 2.2 
6 | 2) | 694°] 67.3 | 659 | 3.5 14 
7 | 30 | 700 | 689 | 676 | 24 13 
gs |.37-|-700 | 698 | 690 | 10 | 08 
The first observation was made in a large unoccupied room where 
the instrument, having been suspended for some hours, indicated 
a temperature of 31.1 degrees Fah. The instrument was then 
quickly removed, together with the detached thermometer, to a 
room at the temperature of 70 degrees, in which all the succeed- 
ing observations were made. The second vertical column ex- 
_presses the time in minutes after the first observation. The 3d, 
Ath and 5th express in that order the temperatures of the detach- 
ed and attached thermometers, and of the mercury in the tube, 
calculated according to formula (1). The 6th and 7th columns 
express respectively the number of degrees the temperature of 
the mercury in the tube was behind the attached and detached 
thermometers. From this table it appears that, after the barom- 
eter had been suspended a quarter of an hour for example, the 
detached thermometer errs as.an index of the temperature of the 
mercurial column by 7.4 degrees, and the attached thermometer 
by 3.8 degrees; and that the corresponding errors, after half an 
hour’s suspension, are 2°.4 and 1°.3 respectively. ‘These errors: 
would have been somewhat diminished if the diameter of the 
tube had been strictly equal to that of the barometric one ; but 
on the other hand they might have been aggravated and rendered 
mote uncertain if the tube had been as long as the baromettic 
one, and had not the temperature-of the room been sustained at 
‘an uniform height. ‘The observations of the table were made 
with care under circumstances favorable to accuracy, and were 
verified by three or four other tables, with which it substantially 
agreed. From the frequency of the observations, some slight ef- 
rors of time may have been committed, but too inconsiderable 0 
affect the particular object of the experiment. 
We conclude therefore that the attached thermometer is an UN” 
certain index of the temperature of the mercurial column, except 
in those rare cases when the. temperature of the air is know? ” 
be uniform, and not even then until after nearly an hour's _ 
pension of the barometer. 
