The following record of an extraordinary spectacle is given in a Canton Gazetteer "Tu the seventh year of the reign of Chia Ching there was observed at Wan-chow (Ch'ing-chou—Island of Hainan) a white rainbow-like vapour that exten from the West to the Milky. Way (Celestial River—Silver River): it continued ten nights and then ceased."
As that latitude (18° N.) might be ex-ceted to afford not infrequent great exh tions of the zodiacal light, and as the case given is the only phenomenon of that description recorded in the Gazetteer, it ocsurred to' me that it was due to a comet whose nucleus was concealed in the mist of the horizon. (Cassinsi, (?) the first observer of the zodiacal light, mistook the great comet of 1668 for that object). I'submitted Chinese statement to the great savant who directs the Zicka-wei Observatory Pore Dechevrens has been so good as to reply. He says: " There were three comets in the three years 1801-1803. One of them reappeared in August 1881, discovered by Pons, which came pretty near the sun, and does not correspond with the Chiness record; and as for the others, they were not of sufficient brightness to be identified with that description, We must therefore look elsewhere for the explanation, and the following seems to meet the case: If one looks towards the west in the months of February, March and April, he may observe for an hour or two after sunset, a band of white light running up to the Milky Way, of the shape of a spear-head. Tt appears like a mass of white vapour which seems to come out of the horizon, appearing in the sky;—that is the zodiacal it, the nature of which is still a problem to astronomy. The brief description of the Chinese record—a white vapour in the West, extending to the Milky Way' well describes the phenomenon, which is always observable at Zi-ka-wei at the above-named periods.""
It would therefore appear that the phenomenon observed on the island of Hainan was merely an extraordinary view of the zodiacal light, its remarkable brightness being due to an exceptional transparency of the atmosphere, coincident, perhaps with an unusual irradiation of that mysterious nebulous mass similar to that described by Humboldt in "Cosmos," as observed from the Plain of Mexico for forty consecutive nights in 1509, or as noted by Nature as occurring on 24th January, 1875, when the zodiacal light was developed with surprising brilliancy. For two hundred years this phenomenon has been a puzzle' to physicists, and, as Arago says, it has been a stumbling block against which innumerable reveries hare been dashed to pieces; and Pdro De-chevrons, unmindful of his own researches, declares it to be an unsolved problem. In 1875 he commenced a series of evening and morning observations, and in 1879 published the result, which refutes all the theories that have been propounded, including that of Laplace, and the ye recent ones which treat it as a toi restrial phenomenon, and due to mag-or to nebulous matter, surround. ing the earth. Having disposed of all previous theories, the Shanghai astronomer arrives at the conclusion that the "substance which causes the phenomenon of the zodiacal light is probably of the same nature as that of the other bodies which compose the solaraystem,—that its dit parts, in order to preserve their stability, must possess motion round the sun in relation to its distance from his centro," a solution of the problem (as far as it goes) which has been accepted by physicists generally.
D. J. Macaoway.
Wenchow, 3rd July.
La Lumi les observation vatoire de Zi Zodiscale Etudiée a'Apri taites de 1875 4 1879 AVObserearly in Spring, hours after sun for a couple of in Autumn in
Text read from the printed page and cleaned; old type leaves the occasional error.