i88 3 .J 
of the Solar System. 63 
of infinitesimal meteors, and that the nebular theory does 
not exclude the formation and absorption of larger meteors 
by a nebular system in formation or formed, and that the 
“ meteoric theory ” is a vague inordinate assertion, but no 
theory at all. I had almost given up my intention, when it 
was revived by some passages in the Anniversary Address 
(1882) of Dr. William Spottiswoode to the Royal Society. 
He said— “ On September 17th an observation apparently 
unique in the history of Astronomy was made by Mr. Gill 
at the Cape, who watched the comet right up to the sun’s 
limb. ... It could not, however, be detected in the sun, and 
this circumstance of appearing neither bright nor dark when 
in front of the sun appears to suggest a very small substan- 
tiality or great separation of the cometary matter.” 
The comet reappeared with a nucleus, or with more than 
one nucleus; the mere insubstantiality and division could 
therefore not have been the sole cause of its imperceptibility. 
— the refraction of light inside the extended and increased 
atmosphere on the night side of the nucleus diminishing in 
size would be in itself an auxiliary reason, but the sentence 
“ The water of the ocean is continually decomposed at the 
limits of the atmosphere, passing into new combinations 
again changing in the course of its return : this electro- 
magnetic process, going on around the sun on a grand scale, 
exists around the planet in a small way” (“On some Proper- 
ties of the Earth,” p. 318) may well apply to a comet near the 
sun. At all events the comet has presented to various ob- 
servers appearances and phases the interest in which may 
perhaps procure some attention from your readers for the 
following development theory of the solar system. 
Dr. Spottiswoode also said — “ Nor must I omit mention 
of Dr. C. W. Siemens’s bold and original theory of the con- 
servation of the solar energy, which has already given rise 
to so much discussion. It will be sufficient for me here to say 
that upon the questions therein raised the last word has been 
by no means said ; and that whether the theory be ultimately 
established, or whether, like a phoenix, it shall hereafter give 
rise to some other outcome from its own ashes, it will ever be 
remembered as having set many active minds at work, and 
will always have a place in the history of Solar Physics.” 
Dr. Spottiswoode attributes to the theory a novelty it cannot 
claim, as he may see from a letter, “ The Sun,” in the 
“ Engineer ” of February 26th, 1869, where the views ex- 
pressed with regard to the maintenance of the “ solar 
energy ” differ only in this, from those of Dr. Siemens’s 
theory, that they distinguish between the action of the 
