VOL. XXI.] PHILOSOPHICAL TRANSACTIONS. 353 



of Auriga. By repeated observations from that night to the next following, 

 the comet appeared to have a proper motion, and to direct its course towards 

 Capella, with little or no deviation from its circle of declination : so that had 

 not the sky been obscured the preceding days, it might have been seen near the 

 north pole. Its velocity was such, that in a day's time it had run through about 

 7° of a great circle ; by which motion it might in less than 4 days nearly reach 

 the pole, and be associated with the pole star. 



By comparing this comet with a star of the 6th magnitude, which Tycho 

 calls the second of those that are in a right line with the pole, it was found 

 that in passing through the horary circle it had got before this star by 15' 53", 

 by which the difference of right ascension ought to be 4° 43', and it was 8' 

 more northerly then that star. Hence the longitude, from the latitude assigned 

 to this star by Tycho, being computed to this time, the comet may be referred 

 to 15° 51' of Gemini, with 37° 25' north latitude. 



This comet moved in the region of the heavens opposite to that of the comet 

 of the preceding year, when nearly at the same distance from the pole as this 

 appeared in at first, and pretty near the same place. That comet of September 

 went in the same track as that observed by Cassini at Bologna in l652. This 

 latter in the month of December came from the southern regions, through the 

 constellations Lepus, Orion, and Taurus, where it crossed the ecliptic at an 

 angle of 76°, and through Perseus and Cassiopeia^ where it disappeared in 

 January l653. Hence it appears that this comet first appeared in the be- 

 ginning of September, in the same part of Cassiopeia where the other disappeared, 

 and from thence proceeding through the shoulders and arms of Cepheus, where 

 it had its greatest latitude from the ecleptic, viz. 76°, it passed between Draco 

 and Cygnus, through the lion's skin in Hercules, through Ophiucus, till it 

 came to the constellation Scorpio, where according to the observations, it con- 

 tinued from the 24th to the 28th of September. From the same observations 

 it was found that it came to its perigeum Sept. 7, in the evening, having a very 

 great apparent velocity, viz. of nearly 10° in a day. 



On the Virtues of the Ostracites. By Dr. Caij. N" 250, p. 81. 



It is stated in this letter that the finely pulverised ostracites, mixed with a third 

 part of chamomile flowers, is a good remedy in gravelly affections. Dose from 

 3S8 to 3i. 



z z 2 



