154 . we REPORT—1858. 
by placing near the luminous body any small reflecting substance, and ob- — 
serving at a distance the illumination which it seems thus to spread to some _ 
distance around. . In a word, he considers the effect in these experiments as 
due to illuminated air, which became visible as distance rendered the glare 
of the bright central point less overpowering to the eye. 
Now this cause he contends cannot produce any effect in the case of 
meteors above the atmosphere, or even its higher rarefied regions. 
“ Meteoric stones, fire-balls, and shooting-stars are only luminous at or 
beyond the boundary of our aérial atmosphere, and cease to be so on their 
entrance into the denser air..... Of the extraordinary illuminating power 
of the fluid which burns around shooting-stars, we may be convinced from 
the vast amount of light which these objects emit, compared with their dimi- 
nutive size. Although some observers, judging from their luminosity, have 
ascribed to them a diameter of from 80 to 120 feet, yet from the manner in 
which so many myriads of them have been lost in the atmosphere during the 
great meteoric showers of 1799 and 1833, we cannot assign to them a higher 
rank than hailstones or drops of rain, so far as actual magnitude is concerned.” 
—(p. 95. 
es Por is led to his explanation of the luminosity of meteors from the 
theory of the solar light, which assigns to the external photosphere of his 
globe the locality of the luminous emanation; and this photosphere he con- 
siders to arise simply from the intense condensation upon and near his surface, 
of the luminiferous ether, the same as the resisting medium, diffused through 
the planetary spaces. He rejects the idea of combustion or chemical changes 
being the source of the sun’s luminosity; as these must in time become 
exhausted, and the supply of light and heat be consequently interrupted. He 
alludes to the query of Newton, asto why and howit was that lucid matter should 
be separated and made to form the sun, while opake matter was distributed 
among the minor bodies of the system. He then adds,—* But there is no 
necessity for this unnatural division of matter; since even if the sun were | 
identical in composition with his attendants, yet in consequence of the great 
superiority of his attraction his surface would necessarily become the focus 
in which the ether of space must display its luciferous properties.”—(p. 98.) 
The same law he conceives to apply to the fixed stars; he rejects the idea 
of the luminosity being due to any mechanical action on the ether dependent 
on the rotation of these bodies, for then Jupiter and Saturn, by reason of their 
far greater rotatory velocity, ought to be more self-luminous than the sun. 
He contends that it is due to “the chemical action which may be expected 
to take place in the etherial fluid as it condensed around the great sphere.” 
—(p- 101.) 
He raises other objections against the theory of Prof. W. Thompson, which 
was briefly described in a former Report, ascribing the solar light to the im- 
pact of innumerable meteors on his surface. 
“The (etherial) fluid is so much rarefied in the interplanetary domain, 
that no chemical changes can take place between its elements, except where 
it is collected around the largest spheres and compressed by their powerful 
attraction. In obedience to the law of gravity, which exerts a universal 
control over all matter, atmospheres of the etherial fluid are collected around 
the earth and the other large planets, but they are not sufficiently dense for 
chemical action, except in cases where they receive an additional pressure 
from meteoric stones sweeping through them with furious rapidity. When 
these cosmical bodies, on falling to the earth’s surface, move in adirection almost 
horizontal, they take a longer course through the verge of the atmosphere, 
and the etherial medium is stimulated to chemical activity by the pressure, 
