: 
4 
J. LeConte on the Silver-Spring in Florida. & 
probably, from two causes: First, because the extraordinary 
transparency of the water rendered subaqueous objects — 
luminous; and Secondly, — the gigantic evergreens whic 
fringed the pool cut off most of the surface reflection, which 
would otherwise have meee the visual impression roduced 
by the more feeble refracted and dispersed light proceeding from 
the objects. The shadow of the surrounding forest formed a 
dark ee, analogous to the black cloud on which a rain- : 
bow is projec 
One of the al phenomena presented by this spring, at 
first sight, seemed somewhat paradoxical :—namely, that when 
i vertically, the depth of the _ appeared to ods exagge- 
The ‘teenies near the surface underwent a somewhat greater ap- 
parent mona oe than those nearer the bottom, but all were ex- 
aggerated in length. This phenomenon was observed in all 
places and under all circumstances, was the same whether viewed 
with one or both eyes; and padi the same appearance 
all observers. The apparent length ri the upper fathom was 
variously estimated at from 8 to 10 fee 
In ordinary cases of considerable sbiiquity of view, it is a 
ites fact, that the water appears to be shallower than it really 
is, in consequence of the seeming elevation of the bottom pro- 
duced by refraction. Hence the foregoing facts in relation to 
the apparent exaggeration of depth, may seem to be income - 
prismatic box with plates of pokes giass at the ends was in the 
compared with the eorstrscyodoe ndle in au. As w e had Sarge 
on it 
Silver Spring, and aided by the 
opin eae wn 
