Morning journal and courier. [volume] (New Haven [Conn.]) 1848-1894, 1888-08-30

fore going fishing on the reefs in the full
glare of the sun, blacken them. Mr.. Aber-
crombY draws attention very naturally to
"the strange anomaly of physiological expe-
rience apparently contradicting the teachings
of pure phpsics. Charcoal black, which is
used in physical experiments as the best abb
sorbent of every kind of heat radiation, is
practically used by three races at least to
protect one of the most sensitive human or
gans from reflected light and heat"
Experience has think sufficiently shown
that snow blindness and snow burn, or SUM-
burn on snow, own the same causes for their
production; and as nowadays both guides
and climbers in the Alps invariably take the
precsution of protecting their eyes with coli
ored spectacles, snow blindness is rarely
heard of. My observations are almost en-
tirely confined to the causes of sunburn.
It will think be readily conceded by Al
pine climbers that sun on the snow burns
more quickly than on rocks or in the heated
valleys at lower elevation. This increased
power of burning appears somewhat singu-
lar when one reflects that the heat rays must
be occupied in the melting of the snow, and
thus rendered latent.
Ironworkers, glassworkers and others are
constantly exposed to heat or four or five
hundred degrees Fahrenheit, and yet do not
become burned and there can be little
doubt that the enormous radiation from
heated rocks and valleys, in addition to the
direct rays of the sun, make up an amount
of heat far greater than is ever experienced
on even very sunny snow slope, and yet
one does not become sunburnt No doubt
the surface of the snow reflects and disperses
much heat, but certainly far less than it re-
ceives, as heat rays are absorbed and rem
dered latent by the snow melting and evapo-
ration. Experience fully corroborates this,
for one may often lie on ones back and free
ly expose the face for long periods to the
Ar16
therefore be some other factor in sunburn
than heat alone.
In discussing the subject with Professor
Tyndall, he added the very interesting and
significant fact that he was never more
burned on snow than while experimenting
with the electric light at the North Fore
land lighthouse, where there was no heat
sufficient to produce such al effect.
I am aware that sometimes, in peculiar
conditions of the atmosphere, the direct
suns rays will burn. / have met with
some singular instances where several per-
sons have been burnt on the same day even
in England, who had never previously suf-
fered in that way. I am further aware
that sometimes (not always) in dead calm
on ships deck one may be severely sun
burnt, and that in boating on a river the
same may occasionally happen. Masks and
wells have been long used as protection on
snow and are more or less successful; brown
wells and glasses in my experience being the
most efficient. As bearing upon this may
mention that friend of mine after an as
cent on snow had an enormously swollen
face, and I observed that in the general
swelling there were many pits or depressions,
and that each pit corresponded to freckle;
the irritating rays had been intercepted by
the brown color of the freckIe. About the
same time encountered paragraph in the
Lancet saying that German savant had
been experimenting on the effects of sum
light on the retina, and had found that it
had destroyed the visual purple of the retina,
but that the action was modified by transs
mitting the suns rays through various col
orsd glasses, and that when transmitted
through brown glass the purple of the retina
was unchanged. l have never seen any cor
roboration of these assertions, but they are
worthy of further consideration. Stimula-
ted by these observations painted my face
brown with water color and spent many
hours on the snow of the Corner Graf on
the same day that about eighty out of one
hundred people who were staying at the Riff
fel Alp went up to witness the frat ascent of
the season of Monte Rosa. In the evening
everyone except myself and my daughter,
who had carefully protected herself with a
brown veil, was more or less severely sun
burnt, while the remaining visitors, who had
| spent the day on the rocks and mountain
| sides in the full sun, were untouched. Con-
nected with this is the fact that visitors to
| the Engadine in winter become extremely
| brown, as though colored by walnut juice,
| while in summer, unless they go on the
| snow, this is not so, although of course the
| heat is greater. I have been there in winter
| and summer, and have had many opportuni-
| ties of confirming this observation. Then
again the very brown color of the chalets Is
only to be seen at high attitudes where snow
| is, and even those parts of the chalets which
| by their position cannot receive rays reflected
From Il T1nFh hoo hvO1 A md
the doors of these brown chalets in which
the COWS are kept the wood is invariably
white and colorless just at that part which
would always have, steaming up, the warm
moist breath of the COWS, and by this moist
ure the reflected rays would be intercepted.
I think that all these observations bear upon
and are related to the question raised by Pro-
fessor Ray Lancaster.
In a comment on Mr.. Abercromby's letter
above mentioned Petrie says, tsWe should
not look at the surface skin, which is con-
structed to bear local variations OF tempera-
ture, &c, but at the delicate tissue beneath.
White skin" he adds, "is translucent, but
black stops out solar energy" It is possible
that sunlight reflected from snow may have
an influence in producing the improved
health of consumptives who remain in the
Engadine in winter, and Mr.. Abereromby re-
minds me that the quality of heat which
causes snow burn is not that which causes
sunstroke. Sunstroke is very rare Gf known
at alD on mountains. Equatorial countries
-Ceylon, Borneo, West Indies, SIc.-are not
the worse for sunstroke; out sub-tropiesl and
semi tropical dry countries, such as Scinde,
northwest Bengal, United States, Italy, &c.
He also says that photography is much slow
er in equatorial than in these latter countries.
The cause undoubtedly is the absorption of
violet and ultraviolet rays by water vapor,
which is in excess near the line Photo
graphy is rapid-except for blue sky-at
| high attitudes.