\ 
444 Mr. Herscuer’s Ober vations on 
lucid circle ACBD; while thofe in the fides m v, nw, will be 
feen fcattered over the remaining part of the heavens at 
MVNW. | 
If the eye were placed ieee without the ftratum, at 
no very great diftance, the appearance of the ftars within it. 
would aflume the form of one of the lefs circles of the {phere,, 
which would be more or lefs contracted to the diftance of the 
eye; and if this,diftance were exceedingly increafed, the whole. 
ftratum might at laft be drawn together into a lucid {pot of any. 
fhape, according to the pofition, length, and height - of the. 
ftratum. 
Let us now fuppofe, that a branch, or fmaller ftratum,, 
fhould run out from the former, in a certain direction, and. let. 
it alfo be contained between two parallel planes extended inde-- 
finitely onwards, but fo that the eye may be placed in the great 
ftratum fomewhere before the feparation, and not far from the. 
place where the ftrata are fill united. Then will this fecond: 
{tratum not be projected into a bright circle like the former, but: 
will be feen as a lucid branch proceeding from the firft, and. 
returning to it again at a certain diftance lefs than a femi-circle.. 
Thus, in the fame figure, the ftars in the fmall ftratum pg, 
will be projected into a bright arch at PRRP, which, after its. 
{eparation from the circle CBD, unites with it again at P. 
What has been inftanced in parallel planes may eafily be ap-: 
plied to {trata irregularly bounded, and running in various direc. 
tions; for their projections will of confequence vary. according. 
to the quantities of the variations in the ftrata and the diftance 
of the eye from the fame. And thus any kind of curvatures, 
as well as various different. degrees of brightnefs,, may be pro- 
duced in the projections. | 
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