544 COSMOS. 



Thang, I insert here a translation from Ma-tuan-lin of the 

 verbal statement of the law of direction of the tail. It is 

 said there : "In general the tail of a comet which is situated 



during a period of 1214 years, certainly a very small error. 

 When Pingre, in the Cometograpliie (1783, torn. i. pp. 259- 

 262), relying upon Diodorus and the Archon Alcisthenes 

 instead of Asteus, places the comet in question in Orion, in 

 OL 102, and still in the commencement of July, 371 before 

 Christ, instead of 372 ; the reason perhaps lies in the cir- 

 cumstance that, like some other astronomers, he characterises 

 the first year before the Christian era, as anno 0. It is to be 

 observed, in conclusion, that Sir John Herschel assumes for 

 the Comet of 1843, seen in full daylight near the Sun, an 

 entirely different period of revolution, one of 175 years; which 

 leads to the years 1668, 1493, and 1318, as the dates of its 

 previous appearances. (Compare Outlines, pp. 208-372, with 

 Galle, in Gibers' Cometenbahnen, p. 208 ; and Cosmos, vol. i. 

 p. 126.) Other combinations by Peirce and Clausen lead 

 to periods of revolution of even 21 or 7 years: a suffi- 

 cient proof how hazardous it is to trace back the Comet 

 of 1 843 to the Archon ship of Asteus. The mention of a comet 

 under the Archonship of Nicomachus, in the JMLeteorol. lib. i. 

 cap. vii. 10, has at least the advantage of showing us that this 

 work was written when Aristotle was at least 44 years of age. 

 It has always appeared to me remarkable that the great man, 

 as he was already 14 years old at the time of the earthquake at 

 Achaia, and of the appearance in Orion of the great comet 

 with a tail 60 in length, should speak with so little anima- 

 tion of so brilliant an object, and content himself with enume- 

 rating it among the other comets " which had appeared in his 

 time." The astonishment increases when in the same chapter 

 the statement is found that he had seen with his own eyes 

 something misty, even a feeble haze (KO/UTJ) round a fixed star 

 in the hip-bone of the Dog (perhaps Procyon in the small Dog,) 

 (Meteorol. i. 6, 9.) Aristotle also speaks (i. 6, 11) of his 

 observation of the occultation of a star in Gemini by the disc of 

 Jupiter. With regard to the vaporous or nebulous envelope 

 of Procyon ( ? ), it recalls to my mind a phenomenon of which 

 frequent mention is made in the old Mexican annals according 

 to the Codex Teller ianus. " This year," it is said there, " Citlalr 



