The Portland daily press., 1885-08-26
The White Mountains Seen From the
Ocean.

To the Editor Of the Press:
In an interesting article copied into yester-
days PRESS from the Squirrel Island Squid,
the statement is repeatedly made that ''the
White Mountains can be seen from the sea
only on very rare days"
This is a mistake, for they are visible in
reasonably clear weather from the sea for at
least forty miles along the Maine coast, and
with great ease, and sometimes for many
consecutive days, from the Cape Lights to
Harpswe!l point, distance of some fifteen
miles. have seen them very frequently
from an open boat in the neighborhood of
Harpswell Neck and even further east. Un-
less intercepted by exceptionally high inter-
vening land they are perfectly visible from
the water from Wells to Sequin at any rate,
and perhaps as far west as the New Hamp-
shire line and as far east as the Sheepscot
entrance.
What thUt writer intended to say probably
was that it was only on rare occasions that
the White Mountains can be seen so far out
to sea that no other land is visible. This
may be substantially true, although l have
always heard that in clear weather in the
morning, so long as Mt. Washington is COW
cred with snow, its peak illuminated by the
eastern sun, is the first land made by West
Indiamen bound for Portland. And this idea
is corroborated by Capt. Johnson's letter,
for he saw SIX peaks when LOG miles distant
southeasterly from the mountains, and there
fore about So miles to the southeast of Port
land.
The approximate rule for determining the
distance at which an elevated object may be
seen from plain, or to speak more correctly
the depression of distant objects by reason of
the curvature of the earth's surface is very
simple, and it is worth remembering. The
depression in feet is two-thirds of the square
of the distance in miles. In other words, a
man standing on the surface of frozen pond
three miles from an observer lying ON the
ice would have to raise lantern six feet
from the pond before it could be seen; at a
distance Of six miles, "a feet, and at dis
times three is nine, and two-thirds'of nine is
six; six times six is thirty-six, and two-thirds
of thirty-siX is twenty-f0ur, &c.
1t should be remembered that this rule
works both ways so that If the observer S
eye is six feet above the surface of ice or wa
ter his horizon will extend three miles in
every direction to level surface, and this dis
tance must be subtracted from the entire dis
tance of the object in applying the rule. Thus
a man standing on the ice would see the Ian
tern nearly nine miles distant if elevated "a
feet, because you could subtract three from
nine, leaving six, and then take two-thirds of
the-Square of six.
Now Mt. Washington is 63O0 feet high and
is about seventy miles distant from Portland
in an air line, Portland being abont the near
est point on the Maine coast Hence it fol-
lows that at the sea level in our harbor. Mt
Washington will be depressed about 1861 feet
leaving about 5000 feet still above the hori,
zon, being almost half the height of the
mountain. IN other words balloon ascend
ing perpendicularly from our city would. al
an elevation of 3,267 feet from the sea levei
aDout three-tifths of mile) afford a view OF
the whole height of the White Mountains
Inc same rule gives the extreme distance al
nlnety-seven miles. Now is the deck of Can't
Johnstons ship was eighteen feet above the
sea, his eye commanded an horizon of six
miles more which would give 103 miles, which
is within three miles of the actual distance
as given by his log 1t may be remarked
that the refraction of light produced by the
atmosphere slightly elevates distant objects