The Bennington evening banner. (Bennington, Vt.) 19??-1961, 1911-07-31
ICEBERG L-r1ClIoN.
Now Marine Thermometer Records Sea
Temperatures Accurately.

temperatures accurately.
During the summer of 1910 expert
ments were made In the northern por-
ton Of the gulf of ST. Lawrence with
o new type Of marine thermometer,
the results of which promise to aid in
the detection Of icebergs in fog and
at night
BY means Of this new type Of ma
rine thermometer II is possible to re-
cord sea temperatures 10 one onethou
sandth Of degree c. The microther
mometer is Of the electrical resistance
type. in which variations of the re-
sistance Of the metal wire serve to
give measure of the changes of tenn
perature of the medium In which the
instrument is immersed The resist
ance Of the wire is made so high that
small variations in temperature pro-
duce comparatively great changes in
the resistance.
The coil is made with resistance Of
1875 Ohms and consists of 300 feet OF
pure iron wire wilk covered and wound
On copper cylinder about four inches
in diameter and six inches wide. The
cylinder is fitted accurately inside Il
second copper cylinder The ends of
the cylinders are carefully sOdered
and rendered water tight, while the
connecting wires pass out through the
middle of the outer cylinder. a stout
copper tube is rlveted on TO the outer
cylinder. 10 which other copper tubes
can be fastened. The wires pass
through lead cable to the chart room,
where they are connected to the bridge
for obtaining n measure OF the tenn
perature resistance Thus the absolute
temperature Us well as the small yaria-
tons can Ice accurately measured. by
means Of II suitable modification and
combination of a Calendar recorder
with the wire bridge II is possible To
record automatically the temperature
to one one-hundredth of degree
headings can be taken every half min
ute, and curves are plotted showing
the variations OF water temperatures.
The instrument is supported over the
side Of the ship about FIVE feet under
the surface of the water. IL has been
found that the exposure Of the bulb OF
the thermometer by the waves pro-
duces no irregularities. as the tempeia-
ture OF air in direct contact with The
sea does not differ from that OF the
water.
Heretofore the proximity of icebergs
has been determined by means Of the
bridge thermometer and by immersing
a mercury or alcohol ship thermometer
| into buckets of water drawn up from
varying depths. These Instruments
are not. as rule. graduated 10 less
than a single degree, which represents
an interval on the stem OF only one
eighth Of nm inch, Temperatures TAX
en- In this manner. even as often as
four times iu an hour In ship going
eight knots. give temperatures only ev.
cry two miles. The temperatures Of
the sea change rapidly in the imme.
date vicinity ~ an iceberg: hence
comparisons made between ohServa-
lions taken at Intervals of even one
mile are Of no value In determining
the presence Of icebergs. The oscilla-
lions can be observed only on n con
tinuous record. On the scale of the
new electrical thermometer single
degree Of temperature is represented
by an interval OF two feet. so that
variations which would be impercepti.
bile on an ordinary thermometer have a
great effect on this sensitive instru.
ment.