1825.] on the Planet Venus, ^ 4\h 



' P. S. Since the above was written, I have completed a series 

 of observations made upon some very fine solar spots, which 

 confirm the statements made in my former paper on the same 

 subject. July 22, 0^ 30"", a spot which had been in view for 

 many days .disappeared. July 21, 23^^25™ (app. time), a spot 

 had entered ;which was not in view at 20^' ; I suppose it entered 

 about the, 2lst, 20'^ for 23^' 25™ it had just entered. This was 

 the lai-gest and finest spot I ever saw. On the 27th, I saw it 

 withovit the aid of a telescope, and it continued visible to the 

 naked eye until the 30th, when, near the centre of the disc, the 

 umbra passed a vertical wire in 5°-5. It was in the centre of its 

 apparent path July 28, V\ 



It had described half its apparent path July 28, P* 

 It entered the disc July 21, 20 



Time of describing half its visible path. . . 6 5 

 therefore it must be visible 12^ 10*^. 



Aug. 3, V\ The spot was very near the edge, so near that it 

 could not remain visible more than eight or ten hours. The day 

 was so unfavourable that I had only this one view of the sun, 

 and this through rather dense clouds. Aug. 3, 21^ there was 

 not the least trace of it. 



It disappeared Aug. 3, 9'^ 



Came into view,, . . . ., July 21, 20 



Therefore in!:<', I'V^^ ,^.'^.'^1 12 13 the spot 



entirely crossed the disc. 



Of the spot which disappeared on the 22d, there was no trace 

 before Aug. 5, 12^' ; I could not see any trace the day before ; 

 and on the 6th, 0^', I saw it ; it had been on the disc about 12 

 hours. 



The spot returned -Aug. 5, 12** 



It disappeared July 22> 



It was invisible during 14 12 



The sum of these two observations is less than the mean period 

 of the sun ; it amounts to 27^^ 1'^ only, which arises from the 

 difficulty of determining it in this manner ; also one of the spots 

 has moved. 



Aug. 1 7, 22'\ The spot which returned on the 5th is quite off 

 the disc ; there is no trace of the feculae near it : therefore it was 

 not in view more than 12*^ 10''. 



Aug. 19, 30''', the spot which disappeared Aug. 3, 9^', has. 

 returned; it may have been visible 12 hours; certainly not 

 more. 



