The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1885-06-13
Echoes From Icebergs.
A Device for AscertainiHg the Presence of
Ecebergs i'm a Fog.

On. Y. SUM-
The present year is recognized among sea
farers on the North Atlantic as an iceberg
year. Every spring, of course, bergs and
foes traverse the steam lines between Eu-
rope and America, but during the present
season they began early, have ever since
continued to be extraordinarily numerous,
and are now reaching ATTITUDES generally
safe from them. The photographic office
announces in its pilot chart for June that
during the present month "the limit of ice
bergs will probably advance as far south as
latitude 390, west of longitude 49," In the
locality here indicated those steamship lines
that habitually sacrifice maximum speed of
passage to safety, by taking ATTITUDES lower
than those of the most direct course, usually
count on freedom from dangerous ice.
The narrow escape of the City OF Berlin
with her fourteen hundred passengers from
being sunk by the huge iceberg she struck,
intensified the interest already excited in
the peris of transatlantic travel. It also dis
closed the fact that many scientific men,
inventors and officers of the navy and the
merchant marine had been at work simulta-
neously on devising means for lessening
these perils. Probably never before has SO
much attention been concentrated on the
subject, at least in the United States. The
National Academy of Sciences discussed it
at its last meeting, and several inventors
have hurried their devices to completion.
Among these perhaps the most noteworthy
are those that are based on producing an
echo from the iceberg or other floating OBJ
ject.
1t need hardly be said that the object
aimed at is that OF seasonaby ascertaining
the presence of icebergs in fog. Prof Bell,
~, flaa hos C1s1 III.
a plan proposed for this purpose by Mr.. E.
Della Tore of Baltimore, and demonstrated
by practical experiments to his satisfaction
and that of Prof. Rowland of Johns Hop
kins University. The trial was made on the
Patapsco, near she head of Chesapeake bay,
and far enough from the shore to escape be-
ing misled by shore echoes. The apparatus
consisted of speaking trumpet attached to
the muZzle of a musket, from which blank
cartridges were fred at passing vessels at
the distance of mile the river steamboats,
and passing schooners invariably returned
echoes, after intervals proportional to their
distances. A family discernible echo was
drawn even from tugboat approaching bow
on quarter of a mile away, while return
sounds from the broadsides of large vessels
at that distance were very marked. Still
another device, already patented, employs a
Dell for producing the sound and an appara-
tus for receiving the echo, the latter being
fastened to the bow, with a telephone for
transmitting the sound to the officer of tn e
deck. It has also been suggested that a
steam whistle can be used to project the
sound instead of the trumpet and gun.
These various devices are thus far expert
mental Prof. Bell does not omit to note
that prolonged rumblings were sometimes
heard when the gun was fired, and more dis
tinctly when the water was rlppled than
when it was smooth. This kind of sound,
if caused by the wavelets in the water, may,
he thinks, "proye disturbing element of
importance when the experiment is tried in
a rough sea-" Some naval officers hold that
this interference would make the proposed
oevice impractical. Prof. Bell, however,
considers it certainly worthy of trial at sea,
while its inventor, we believe, says that ii
has already been tested on the ocean and
has there secured perceptible echo from
an iceberg. The results of these new ex-
| periments, at all events, will be eagerly
watched, since it is evident that no existing
| appliances for ascertaining the presence of
icebergs in fogs are trustworthy. A rapid
| fall in temperature is sometimes an indica.
| ton, but other elements, not emitting the
| high speed of the steamers, may prevent
| this from being sufficient, and certainly il
was no adequate warning for the City Of
| Berlin. Again, should the sound test, when
| perfected, prove efficient, it would serve as
| protection against those derelct water.
logged hulks which sometimes float fol
months across the steamship routes.