[ 4^6 ] 
1 2. Thefe protuberances and indentures, lb eafily 
meafurable by the micrometer, whilft the telefcopie 
wires appeared ftrait, enabled me to conclude, that cer- 
tain ffrata or the atmofphere, having different refradtive 
powers, and lying horizontally acrofs the conical or 
cycloidal fpace traced out by the rays, between the 
eye and that part of the atmofphere firff touched by 
the rays, muff have been the caufe of fuch apparent 
protuberances and indentures, in an horizontal di- 
rection, acrols the Sun’s vertical limbs ; and alfo, that 
the bottoms of thofe protuberances and indentures 
muff be confiderably enlarged, and removed, to ap- 
pearance, farther from the center of the difk, than 
they would have been, had there been no fuch ffrata 
to refradt. 
13. Before fun-rifing, when the Sun has been near 
the tropic, and the Iky, at the utmoft extent of the 
horizon, hath appeared very clear, and when certain 
fogs have appeared in ffrata placed alternately between 
the hills, and over intervening rivers, vallies, &c. fo 
as to admit a fight of the rifing Sun over thofe fogs, 
I have often obferved, with admiration, the aioff di- 
ffant trees and bulhments, which at other times have 
appeared Imall to the naked eye, but whilft the Sun 
has been palling along a little beneath the horizon, 
obliquely under them, juft before fun-rifing, when 
the Sun has been thus approaching towards and be- 
neath any trees and bufhments, they have grown ap- 
parently very large to the naked eye, and alio through 
the telefcope j and they have loft that apparent large- 
nefs, as the Sun has been paft by them. Thus, a 
few trees ftanding together on rifing ground, at the 
diftance of a few miles, have appeared to grow no 
into 
