Mifcettanea Curiofa. 299 



ceflary to move the Micrometer for meafur- 

 ing its diftance from Alcor that may be done 

 another Night (and it is not necefiary to be 

 done at one Observation) for that diftance, 

 and cannot be difcernably varied in a Night 

 or two. 



I fhall give you no farther trouble at pre- 

 fent, but fubfcribe my felf, Sir, 



Yours^ &c, 



