31 



of 1871, have but little agreement with Sir J. Herschel's 

 monograph. 



It will also be observed that a very considerable increasing 

 the number of stars has taken place, there being now visible 

 in the field of the telescope one hundred and seventy of the 

 7th, 8th, and 9th magnitude, as compared with one hundred 

 and thirty-four in the drawing of last year. 



The boundary of the dark space has now six openings, as 

 shown in the drawing, but is gradually becoming less distinct. 



For the purpose of seeing the original lemniscate, eye- 

 pieces of 60, 80, and 130 powers were used, but without avail. 



[In the present drawing, the term ** line of sight " has been 

 omitted, some exception having been taken to it, but I find it is 

 still in use — Fraser's Magazine for January, 1872. The term oc- 

 curs twice in Mr. Procter's article, *' New Survey of the Northern 

 ^eayens," page 91.] 



