DOI Page / Citation link:
https://doi.org/10.11588/diglit.18733#0031
[• 25 ]
tice adventitious ones, the principal of which
is the rarity or density of the medium through
which objefts are seen. To prove this demon-
strably, I have only to request your recollection,
that in the late foggy weather you could see,
searce further than you could feel; or if the
eye had strength enough to diseern objests im-
mediately around it, those but a little way re-
moved, were involved in uncertainty. The
objefts were in their places; in full propor-
tion ; and your visual powers in vigour; but the
gross medium prevented their usual perception.
This is an extreme instance os what is perpe-
tually occuring, only in a lower degree.
The air is a very subtile and transparent
fluid, and in a small space, or distance, has no
perceiveable effeft; but in objests very re-
mote, we diseover its power. A mountain
at hand, is green, or brown; the same moun-
tain seen from afar, is blue ; from hill to hill
may be clear ; the lower grounds (as affording
mo st vapour) confused ; the upper part of the
steeple of a great church, distinft; the body
of the same church, scarcely visible.. This
one great source, branches out into numberiess
variations, producing effefts corresponding to
the seasons, and the weather; to climates, and
regions. A certain English traveller in Spain
24. D tells
tice adventitious ones, the principal of which
is the rarity or density of the medium through
which objefts are seen. To prove this demon-
strably, I have only to request your recollection,
that in the late foggy weather you could see,
searce further than you could feel; or if the
eye had strength enough to diseern objests im-
mediately around it, those but a little way re-
moved, were involved in uncertainty. The
objefts were in their places; in full propor-
tion ; and your visual powers in vigour; but the
gross medium prevented their usual perception.
This is an extreme instance os what is perpe-
tually occuring, only in a lower degree.
The air is a very subtile and transparent
fluid, and in a small space, or distance, has no
perceiveable effeft; but in objests very re-
mote, we diseover its power. A mountain
at hand, is green, or brown; the same moun-
tain seen from afar, is blue ; from hill to hill
may be clear ; the lower grounds (as affording
mo st vapour) confused ; the upper part of the
steeple of a great church, distinft; the body
of the same church, scarcely visible.. This
one great source, branches out into numberiess
variations, producing effefts corresponding to
the seasons, and the weather; to climates, and
regions. A certain English traveller in Spain
24. D tells