Suns observed and computed right ascensions , &c. 457 
Table VII. — continued. 
The bulbs of the thermometers, were now placed under 
the covers* of each axis and brace, and the results were as 
follow. 
Times of Comparison 
h. m 
9 57 
IO I 
Thermometers on the 
Western Axis. 
Thermometers on the 
Eastern Axis. 
10 6 
IO 13. 
Mean == 91 .7 
Mean — 72 .2 
Hence, difference of temperature = i9°-5- 
Thermometers under the covers of the braces, afforded results nearly the same as 
the above. Not a cloud passed over the sun, during the experiments. 
Exposure of the Instrument, September 3. 
Times of Comparison, 
h. m. 
10 33 
IO 36 .... . 
Thermometer on the 
Western Axis. 
Thermometer on the 
Eastern Axis. 
10 39 
10 42 
Mean 2= 83 .1 
Mean ~ 70 .8 
Hence, difference of temperature = *3°.7. 
Note . — The instrument during this day’s experiments, was deprived of all its 
coverings. The exposure commenced at 9 h 43' sidereal time, but no comparison 
of the thermometers was made, until io h 33'. 
Exposure of the Instrument, September 5. 
To procure more decisive differences of temperature, be- 
tween the western brace and axis, and those on the eastern 
side of the instrument, the former, were now enveloped in black 
woollen cloth, the latter, in white ; the western half also of the 
centre piece, was covered with black , whilst the eastern half of 
it was enclosed, in white cloth ; the telescope tubes, however, 
* Vide page 434. 
