OF THE SUN WITH THAT OF THE FIXED STARS. 
25 
Appendix. 
I. Observations of a reflected image of the Sun, compared with a similar 
image of a Candle. 
The sun’s image, reflected from a thermometer-bulb filled with mercury, is 
viewed from a distance by the observer through a telescope, with power 36, 
and two yellow glasses at the eye-piece. The image of a candle, reflected 
from a similar bulb, is viewed through a lens of from 2 to 2i inches focus ; 
and the distance of the candle is varied, until its image appears of equal 
brightness with the image of the sun. 
Date of the Observation. 
B 
Diameter of the 
thermometer- 
bulb, for Q, in 
inches. 
D 
Distance of the 
thermometer- 
bulb, for ©, in 
inches. 
b 
Diameter of the 
thermometer- 
bulb, for Candle, 
in inches. 
d 
Distance of the 
thermometer- 
bulb, from the 
Candle, in inches. 
l 
Focus of Lens 
for viewing the 
image of Candle, 
in inches. 
1826, March 10 
•19 
1440 
.44 
68 
2.0 
1827, March 14 
.26 
2928 
.26 
42 
2.5 
.... March 16 
.26 
2928 
.26 
28 
2.5 
.... March 16* 
.11 
1440 
.26 
41 
2.5 
.... March 25 
.26 
2928 
.26 
36 
2.5 
.... March 25* 
.11 
1440 
.26 
57 
2.5 
.... April . 6 
.11 
1440 
.26 
49 
2.5 
II. Observations of Sirius, compared with a reflected image of a Candle. 
Sirius is viewed by the observer through a telescope, with power 36, and two 
yellow glasses at the eye-piece. The image of a candle, reflected from a ther- 
mometer-bulb filled with mercury, is viewed through a lens of from 2 to 2i 
inches focus ; and the distance of the candle is varied, until its image appears 
of equal brightness with that of Sirius. 
Date of the Observation. 
0 
Diameter of the 
Thermometer- 
bulb, for Candle, 
in inches. 
$ 
Distance of the 
Thermometer- 
bulb, from the 
Candle, ininches. 
X 
Focus of Lens 
for viewing the 
image of the 
Candle, in inches. 
Remarks. 
1826, March 15 
.44 
216 
2.0 
.... March 19 
.44 
165 
2.0 
Very bright night. 
1827, Feb y . 14 
.44 
246 
2.0 
Feb y . 15 
.44 
170 
2.0 
Very bright night, 1 0 h 30 m . 
.... March 14 
.26 
102 
2.5 
.... April . 4 
.26 
90 
2.5 
.... April . 9 
.26 
93 
2.5 
7 h 15 m . 
III. Observations of « Lyrse, compared with a reflected image of a Candle. 
1827, April 9 
.26 
276 
2.5 
MDCCCXXIX. 
E 
