e._, the diffusion of the reflected rays, can be changed
from a ratio of 1 in 5,040 to that of 1 in 10,241. This has been effected
by employing heaters respectively 10 inches and 20 inches in diameter.
With reference to the "low" solar temperature pointed out, it will be
perceived that the adopted expedient of increasing the density of the rays
without raising the temperature by _converging_ radiation, removes the
objection urged.
Agreeably to the dimensions already specified, the area of the 10-inch
heater acted upon by the reflected solar rays is 331.65 square inches, the
area of the 20-inch heater being 673.9 square inches. The section of the
annular sunbeam whose direct rays act upon the polygonal reflector is
3,130 square inches, as before stated.
Regarding the diffusion of the solar rays during the investigation, the
following demonstration will be readily understood. The area of a sphere
whose radius is equal to the earth's distance from the sun in aphelion
being to the sun's area as 218.1 squared to 1, while the reflecter of the solar
pyrometer intercepts a sunbeam of 3,130 square inches section, it follows
that the reflector will receive the radiant heat developed by 3,130 /
218.
Pages:
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37