266 
SIR J. CONROY ON THE AMOUNT OF LIGHT REFLECTED 
the axes of the flames, which were about 15 mm. in diameter; in all the others, for 
which portions only of the flames were used, the distances were measured from the 
apertures in the chimneys. 
The same glass was used for these experiments that had been employed in the 
transmission experiments already described. In order to prevent the light reflected 
from the second surface of the glass reaching the photometer the measurements were 
made with prisms cut from the 18'5 mm. plate of crown glass, and from the flint 
glass block; one face of each of these prisms was formed by one of the original 
surfaces of the glass, and these faces, which had not been repolished, were used for 
the reflection experiments. 
Table VII. gives some of the actual measurements made with the prism of crown 
glass. The first four columns contain measurements made with the light from the 
whole surface of the flames ; the others with light from the central portions only. In 
the first set the light was incident upon the glass at an angle of 6° 17', and in the 
second at 6° 47'. 
Table VII. 
A. 
B. 
Direct light. 
Mean with 
direct light. 
Ileflected light. 
Jlean with 
reflected lignt. 
Direct light. 
Mean with 
direct light. 
Reflected light. 
1 
Mean with 
reflected light. 
cm. 
cm. 
cm. 
cm. 
cm. 
Cm. 
cm. 
cm. 
128-8 
117-0 
129 8 
118-9 
127-8 
iso -1 
127-8 
129-4 
128-8 
28-8 
30-1 
28-0 
28-0 
28-7 
118-1 
119- 3 
118-6 
120- 1 
118-9 
24-0 
24-2 
23- 8 
24- 3 
24-1 
127- 6 
129-1 
1 
126-3 
128- 0 
127-9 
29 2 
28- 7 
27-7 
29- 6 
28-8 
119- 3 
120- 2 
118-3 
120-3 
119-4 
23- 7 
24- 2 
24-1 
24-7 
24-2 - 
126-7 
128-1 
126-1 
128-0 
127-2 
28-5 
28-7 
28-0 
28-6 
28-4 
119-2 
119-6 
118-3 
118-1 
118-8 
24-1 
25 0 
24-5 
24-2 
1 
i 
24-4 i 
; 126-3 
127-9 
1 
127-0 
27- 8 
28- 9 
27- 6 
28- 4 
00 
118-2 
118-6 
118-3 
23- 5 
24- 3 
24-2 
24-3 
24-1 
i 126-9 
128-0 
118-1 
117-5 
12.5-8 
118-5 
127-3 
1 
119-6 
From the mean residts the values of x^, x^, {x — x-^) and (x — x.,) were obtained, 
and from these the percentage amount of light reflected by the glass calculated by 
