Idaho semi-weekly world. [volume] (Idaho City, Idaho Territory) 1875-1908, 1888-10-19
AN IMPORTANT MATER.
Nose Blackening Said to lie preventive
of snow Blindness.

lItiilh tfSlttT , lHtittAA Va
inc as preventive OF snow-bllhohesS,
NAV I offer some observations when
have made in my many wanderings IN
the higher Alps in early summer when
/ have necessarily had much expert
ence of the effects of snow on the hui
man body.
But first | should like to draw at
tention to letter of Hon, kaiph
Abercromby, relating some expert
ences on nose and face blackening III
Morocco to prevent sand-glare, IN flJl
to prevent water-glare and in Slkklm
to prevent snow-glare. 1t was curious
that the Fiiians, who ordinarily paint
ed their faces white and red for orna-
ment, would, before going fishing on
the reefs in the full glare Of the sun,
blacken them. Mr.. Abercromby
draws attention naturally to "the
strange anomaly of physiolog-
ical experience apparently con-
tradictlng the teachings of pure
physics. Charcoal black, which is
used in physical experiments as the
best absorbent of every kind of heat
radiation, is practically used by three
races at least TO protect one of the
most sensitive human organs from re-
fiected light and heat"
Experience has. think, sufficiently
shown that snow-blindness and Esnow-
burn, or sunburn on snow, own the
same causes for their production; and
as nowadays both guides and climbers
in the Alps invariably take the precau-
ton of protecting their eyes with col
ored spectacles, snow-blindness1 is
rarely heard of. My observations are
almost entirely confined to the causes
Of sunburn.
1t will, think, be readily conceded
by Alpine climbers that sun on the
snow burns more quickly than on rocks
or in the heated valleys at a lower ele-
walton. This increased power OF burn
ing appears somewhat singular when
she reflects that the heat rays must be
occupied in the melting of the snow
aud thus rendered latent
hon-workers, gass-workers and
others are constantly exposed to "a
heat of 400 deg or 800 deg. f. and yet
do not become burnt; and there can be
little doubt that the enormous radiation
from heated rocks and valleys, in ad-
dition to the direct rays of the sun,
makes up an amount of heat far great
en- than is ever experienced on even a
sunny snow slope, and yet one does
not become sun-burnt. No doubt the
iurface of the snow reflects and dis
perses much heat, but certainly fan
less than il receives, as heat rays are
absorbed and rendered latent by the
snow melting and evaporation. Elk
perieuce fully corroborates this, fol
one may often lie on ones back and
/ freely expose tho face for long periods
to the sun and yet remain unburnt
There must, therefore, be some Other
fuctor in 5unburn than heat alone.
In discussing the subject with Prof
Tyndall he added the interesting ant
significant fact that he was never NOR,
burnt on snow than while experiment
ing with the electric light at North
Portland Lighthouse, where there
was no heat sufficient to produce sucl
an effect.
am aware that sometimes, in pc
cuIiar conditions of the atmosphere
the direct SUMS rays will burn. hav,
met with some singular instances where
several persons have been burnt on tn,
same day, even in England, who hat
never previously suffered in that way
| am further aware that sometime,
(not always in a dead calm on a ship
deG4. one may be severely burnt, and
thiS boating on river the same mal
occasionally happen. Masks and vail
have been long used as a protection Oh
snow, and are more or less successful
brown walls and glasses in my expert
ence being the most efficient As bear
ing upon this | may mention that
friend OF mine after an ascent on snoy
had an enormously swollen face. and
observed that in the general swellin
there were many pits or depression:
aud that each pit correspondent to
freckle, The irritating rays had bee
Intercepted by the brown color of tn
freckle. About the same time | ell
countered a paragraph in the Londo
L02ccnt saying that German savar
had been experimenting ON the effe,
OF sunlight on the retina, and ha
found that it had destroyed the visu,
purple Of the retiua, but that the actio
was modified by transmitting the sun
rays through various colored glasses
aud that when transmitted throug
brown glass the purple of the retiu
was unchanged. robert L. Boclcs,
Nature.