524 - Mr. herschel’s Agronomical Observations 
took the diftance according to this judgment as well as I 
could. 
The third method I took was the following, which, 
indeed, I look upon as the beft of all, and which I there- 
fore moft frequently put in practice. I took a view of 
feme neighbouring fhades of rocks- or mountains, if 
there happened to-be any near, and directed the meafure 
of the micrometer by them, as they plainly pointed out 
the direction of the illuminating ray ; or, which is the 
fame thing, indicated the line perpendicular to a line 
joining the cufps. 
Mons Leucopctra was meafured by this laft method, 
which circumftanee I have mentioned in my obferva- 
tions of the 1 2th of March,, where Ifaw the whole rock 
and its higheft point, as well as the whole fhade, and its 
laft termination, upon very even ground, at the fame 
time that I directed my micrometer in that line, to take 
the projection on, of the above mentioned mountain. 
Sometimes I compared together a meafure taken in 
the direction on, and one taken in the direction rn \ but 
as moft of my obfervations were made upon mountains 
not fituated near the cufps or limb of the Moon, I never 
found fo much difference between thefe two meafures, 
that it could have occafioned any very material error, if 
I had intirely negleCted in 
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