The Camden chronicle. (Camden, Tenn.) 1890-current, 1903-07-17
SCIENCE NOTES.

According to Sir william
tonDyor. director OF Kew g
some experiments undertakes
Chelsea, a suburb OF London. dufh
a fog went to prove that In one week
no less than six tons Of deposit 10 tho
square mile were deposited. Not only
did this consist OF SCOT. but a consid-
cradle variety Of twry hydrocarbons
we're also deposited. which had very
injurious effects upon plant and ait
NAL life
Professor Langley of the Smithso
ian institution. has discovered by ex
pertinent that II the air In a long
telescope be agitated a perfectly quiet
image of a star or of any other OBJ
ject may be obtained Astronomers
have been bothered by the unsteadi-
ness Of the air ever since the Nele-
scope was invented and for ia rea-
son observatories have been bl on
elevated ground wherever practicable.
The result obtained by Professor
Langley may be due to the fact that
the agitation Of the air inside the
telescope Offsets the unsteadiness Of
the outer air, and thus equalizes the
conditions.
A paper pointing out the mana I'M
projections of Photographic sh Ars
was read before the American SocP4y
for the Advancement of Science at its
recent meeting. Investigation has
shown that the better grade of shut
ters are fairly constant in operation.
but the actual duration Of exposure
is often not oven approximately that
indicated by the maker. Different
shutters Of the same make and form
give different exposures when set for
the same time. Some of the cheaper
makes, designed to give long, medf ,
and short eXposure5 give equal
posures in the three cases. All this
may account for the difficulties that
many amateurs have in their work.
1Ss
Objects too small or distant to be
! seen-like fixed stars-are made per.
ceptible by their light. Taking advan.
tage of this fact, Siedentopf and Zsig.
mondy have magnifed strongly ilpm.
/ mated particles. and in this way have
made visible the diffraction discs pf
specks Of matter approaching mole
! cules in minuteness. Their observa-
/ tons were made upon particles of
gold embedded in ruby glass. From
the known quantity of gold and the
number of discs, it was calculated that
each particle, with an apparent diam
eter of 1-50,000th of a millimeter. and
it was further shown that the limit OF
magnifcation would be 10000 diane
ters. The greatest powers Of tn
method would show particle he
10 times the diameter Of a molecu&.
In the body changes that take place
as we grow old, Metchnikoff and other
psychologists suppose that an i'm.
portant part is taken by the phago-
cytes, or devouring cells. Some years
ago it was made to appear thatlsome
Of these cells are color eaters Rid
that they whiten the hair by SEEING
the pigment grains and conveying
them into the skin or out of the organ
ism. On further study the theory has
been evolved that old age itself is due
to phagocytes that destroy the nerve
been found in the brains of many old
people and old mammals as we'll as in
persons suffering from nervous dis.
ease, but in no case have they been
known to reach such develOpment-or
to have so nearly taken the place of
the nerve vells-as in the brain of a
parroquet that died at the great age