Mr ROTHMANS OBSERVATIONS OF HALLEY'S COMET. 501 



Oct. 27. 

 Watch slow 2"". 36'. 



Ingress. 



Egress. 



The Star is in Histoire Celeste, p. 290, b. Transit at 17'' . 8™ . 32'. 



To reduce these observations, it is necessary to allow for the dif- 

 ferences of refraction in right ascension and declination, and also for 

 the proper motion of the Comet. This proper motion was obtained, 

 wherever it was possible, from the observations themselves : where this 

 could not be done, as in the case of single observations, I made use of 

 Mr Stratford's Ephemeris. 



Ss 2 



