Page:The story of the comets.djvu/191

X. having a peculiar appearance on the evening of June 30. He says that the sky had a yellow, auroral, glare-like look; and that the Sun, though shining, gave but a feeble light. The comet was plainly visible during sunshine at 7.45 p.m. In confirmation of the statement that there was something unusual and indescribable happening, Lowe adds that in his parish church the vicar had the pulpit candles lighted at 7 o'clock, which proves that some sensation of darkness was felt even while the Sun was shining. Though unaware at the time that the comet's tail was enveloping the Earth, he was so struck by the singularity of what he saw that he made the following entry in his day-book:—"A singular yellow phosphorescent glare, very like diffused Aurora Borealis, yet, being daylight, such Aurora could scarcely be noticeable." The comet itself, he states, had a much more hazy appearance than on any subsequent evening.

De La Rue attempted to photograph the comet, but it left no impressions on 2 collodion plates, although neighbouring stars did impress themselves on the plates.

No fewer than 11 envelopes were seen to spring from the head of this comet between July 2, when portions of 3 were in sight, and July 19; a new one rising at regular intervals every second day. And their evolution and dispersion took place with much greater rapidity than was the case with Donati's Comet in 1858; each envelope taking but 2 or 3 days to go through its various changes instead of 2 or 3 weeks.

On the question of the polarisation of the light of the comet, Secchi said:—

"The most interesting fact I observed was this: the polarisation of the light of the comet's tail and of the rays near the nucleus was very strong, and one could even distinguish it with the band polariscope; but the nucleus presented no trace of polarisation, not even with Arago's polariscope with double coloured image. On the contrary, on the evenings of July 3, and following days, the nucleus presented decided indications, in spite of its extreme smallness, which, on the evening of July 7, was found to be hardly 1".

"I think this a fact of great importance, for it seems that the nucleus on the former days shone by its own light, perhaps by reason of the incandescence to which it had been brought by its close proximity to the Sun.