49-4. 



jih rothman's observations of halley's comet. 



The Star is in the Histoire Celeste, p. 52, March 4, 1794, observed 

 at 3rd wire 6'\ 8" . 48^5. 



These are the first observations I ever made with the ring-micro- 

 meter : the fractions of seconds of time were not noted. 



Ingress, 

 h. m. .1. 



Comet 13 . 57 . 18,8 

 Star 59.11,6 



Comet 14 . 2 . 5,2 

 Star 4 . 35,4 



Comet 15.48,4 



Star 17.49/) 



Sept. 22. 

 Watch fast 3"". 36'. 



Egress, 

 h. m. 8. 

 13 . .69 . 19,f> 1 



14. 0.55,8 



14. 4.27,4 



5 . 24,6 



17 . 5.3,6 

 19. 17,0 



Inner Ring. 



Comet in the lower half 



of the field: 

 Star in the upper 



throughout. 



I imagined at first the Comet too far from the Star to be compared 

 by means of the inner ring, and accordingly made one observation with 

 the outer ring. Finding however measurements with the inner ring 

 practicable, I proceeded to make them : always preferring to do so 

 when possible, as more dependence can be placed on the perfect circu- 

 larity of the latter. For this reason the single observation of the outer 

 ring has been rejected. 



