( *77 ) 
and the Lines they defcribe in feveral Months of the 
Year. The daily Stages in both Figures are exadf^ or 
if they feem otberwife, it is by reafon the Observations 
were made at different times of the Day ^ as one in the 
Morning,, the other fome following Day in the Evening, 
or Afternoon. But the Declinations of the Spots, or 
their diftances from the Sans Northern or Southern 
Limb, arelefs exa& in the fecond Figure than the firfl 5 
in which latter they are very near the truth. 
And the Caufes of the Defefts in the 2d Scheme I 
(ball mention, to prevent the fame Errors in others I 
my felf ran into. 
i. The Diminution of the Suns vertical Diameter 
by the Refraftions was the principal caufe of my Errors. 
This, altho' I was fufficiently aware of, yet I did not 
think had been fo considerable, for want of experiment- 
ing, or well confidering the Matter : For I have fome- 
times found the perpendicular, or vertical Diameter of 
the Sun diminKhed* from. 32' 21" on the Meridian, to 
26' 3" at the Horizon, in one and the lame Day. 
2v For the fame reafon I was not aware of the time 
being fo long belore the Sun goes round, as I found 
i*. 
3. Another Error was meafuring the Suns Ima^e on 
the Scene of white Paper, with the Shade of the Micro- 
meter 5 and not by looking through the Tube, and fo 
clafping the Limb of the Disk wi h the parallel edges of 
the Micrometer. The former, altho’ pra&ifed by fome 
eminent Aftronomers, is a far more eafy and indulgent, 
than accurate way. 
