ioi4 Mr. wales on the 
inches. I ufed a magnifying power of about 75 times 
for the beginning and end, and of about 50 or 55 times 
with the micrometer, in meafuring the Sun’s diameter, and 
the diftances between the two cufps of the luminaries. 
The micrometer, which is an exceeding good one, 
was made alfo by Mr. short. The divided glafs is not 
achromatic, but only a Angle lens, whofe focal length is 
about 28 feet 5^ inches; but as I have not had an oppor- 
tunity of examining this point myfelf by adjufting the 
telefcope to parallel rays without the micrometer, and 
then putting it on, and meafuring the diftance at which 
objedts -are Teen diftindtly, I have affumed the Sun’s apo- 
geal diameter to be 31' 28" as given by Mr. short; and 
on that hypothefis the following redudtions of the parts 
of the micrometer are made. Its error was determined 
immediately before the beginning of the eclipfe, by 
meafuring the angle fubtended by a fmall ball which is 
on the top of the fpire of St. Bride’s Church, in Fleet 
Street, alternately before and after o, or the beginning of 
the divifions of the fcale : thefe meafurements were as 
follow : 
