The Sun.
London, England, 1850-05-10 00:00:00

POLYTECHNIC INSTITU TION.

The second lecture of Dr. Bachhoffner proves no
less interesting than the first of his series, on the
Philosophy of Scientific Recreation. The Doctor, in
this explains the principles governing the effects
commonly known as Light, Shadow, and Colour.
Although at first a subject seemingly so devoid of
popular interest, under such skilful management it
became an all absorbent theme. The most pro-
minent features connected with the philosophy of
sight were briefly entered into by the Doctor, one
and all tending, in their minute perfection, to evi-
dence the wisdom and skill of an all-wise Creator.
Had one little muscle been forgotten in the construc-
tionof the eye, we should have been under the necessity
o f using one hand to adapt the eye to observe any ob-
ject presented in the other. The involuntary motion,
or winking, of the eye could have as little been dis-
pensed with, serving, by its peculiar motion, to clear
and preserve the eye from all adventitious matters.
The movement of the upper lid of the eye is,
as explained by Dr. Bachhoffner when carried
on involuntarily, so extremely rapid as to preserve
the image of the object without cessation upon the
mind ; but however quickly this winking be performed
designedly, we cannot prevent the momentary loss of
the image during such process. This the Doctor made
the basis of a number of explanatory and highly
curious experiments. The next point touched upon
was the operation of seeing, not performed, as we
may imagine, by the eyes, but by the mind. Dr.
Bachhoffner told us we do not see by our eyes any more
than a " Camera Obscure," capable of producing the
image
t ofm machine)
ionbe)je,ct
can presentedseethe image
ens
ot heproduced.ground
eye performs the part of such " camera, producing
the image, while the brain is the organ of sight ; and
it
is the brain which sees. Therefore the Doctor's as-
sertion is (however unintelligible it may
, appear) cor-
rect—" We do not see with our eyes. Much more
of interest remains to be noticed.

SOUTH AFRICAN EXHIBITION.
We took an early opportunity of visiting this very
curious and interesting collection, and were forcibly
struck with the beauty of the natural objects shown,
the singularity of those rude specimens of art in its
infancy exhibited, and, above all, with the taste dis-
played in the arrangement of the whole. To the
lovers of natural history this exhibition recommends
itself by the number, importance, and high state of
perfection of the objects introduced to our notice.
To travellers, or at least to those who like to read of
travels, it presents an opportunity seldom afforded in
books, by presenting undeniable evidence of things
and acts which in type alone might be deemed in-
credible ; indeed, before we had seen and inspected
the whole, we became so impressed with a sense
the reality of certain terrific scenes, minus their
orld
dan-
ger, that we occasionally fancied we were transported,
mentally, of course, to those very parts of
of this
which the courageous and enterprising
ownerthe idea of the
collection has visited, and trembled at he must
perils he must have faced—of the i
must have
have overcome—of the hardships he the world
ance used by him
en-
dured. The very means of ct.,sn
We were equally
is an object of great
refinement could be found com-
bined to see that
alities required to go through-
during a portion, at least of hiestvt.in-aYvels,now exhibited,
bined with those ruder
equherculean task, evidenced by
But of all curiosities in connexion
-eusscraiptions, which reflect great credit
upon the writer...
n the most remarkable is doubtless
with this exhibition tasteful,wlat ap pears
poetical tod
in the. owner's Bushman, a 'ofthe
mountainous South native
Africa, who accom-
panied and for four years faithfully served the enter-
prising be appreciates, of visiting this (to him)
prising traveller,
districts of
who now has the good fortune,
t, ohbi
ce b f
wo uehdo
and
most
singular country : he seems mild tempered and
sicr,ple-hearted, gave us proof of his having already
made some
andpro
progress in the arts of civilization by
having discovered the popular way of allaying
thirst
in this country, and evincing a proper sense of its
efficacy by his willingness to try the experiment;
upon which and other points we were Ow: to exchange
a few words with him. If we may judge of the
future popularity of this exhibition by the growing
interest we took in it as we proceeded to view its in-
structive details, ,e e can only say that see hope, when
next we visit it again, to find it whaVit, deserves to
be, a favourite with all who seek rational and useful
amusement.

At the rent audit of the Marquis of Lansdowne,
he d last week, a reduction of 10 per cent. was made upon
the rents. His Lordship has given directions for a fresh sur-
vey of the whole of his Wiltshire estates.—Bath Chronicle.