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May 2, 1884.| 
ICEBERGS AND ICE-FLOES. 
In the Atlantic, the great oceanic base for 
by far the larger number of arctic expedi- 
tions, icebergs sometimes reach as low as the 
latitude of Boston. ‘They are to be dreaded 
mostly in the night, and sometimes in very 
heavy or foggy weather. This danger, there- 
fore, steadily decreases as the ship nears the 
pole; and, when she passes the arctic circle far 
enough to encounter perpetual daylight, it 
ceases. It is in the lower latitudes, and es- 
pecially during dark, foggy nights, so common 
to those regions, that the sharpest lookout 
must be kept ; and here, also, the berg, meeting 
warmer waters and climate, is, in its disinte- 
eration, widely surrounded by a vast débris of 
smaller masses, most of which are equally as 
dangerous as the parent. 
There is one peculiarity of icebergs that is 
fortunate for those cruising in their vicinity ; 
and that is, their visibility at long distances 
during dark nights and heavy weather. I 
remember on the 10th of July, 1878, while 
making for the eastern entrance of Hudson’s 
Strait, and while off the Labrador coast, our 
second mate, a keen-eyed Scotchman, caught 
the faintest glimmer ahead, during a misty 
morning, about two o’clock, when daylight was 
just commencing to break. He pronounced it 
an iceberg, and estimated it to be two or three 
miles away; and, wearing ship and laying to, 
we found in the morning that he was not any 
too far out of the way. ‘This colossus of ice 
was flanked on either side by its débris for 
three or four miles, some of the pieces standing 
fully as high as the foremast of our little 
schooner. With my unseamanlike eyes, even 
with the aid of a powerful marine glass, I could 
only make out the slightest break in the inky 
clouds hugging the horizon; and the mate told 
me that the navies of the world, a score abreast, 
could have passed between us and the berg and 
been invisible. It is a peculiar sheen of their 
half-polished faces, characteristic of glacier ice, 
that penetrates so far, and under circumstances 
where a bank of snow or a ship’s sails would 
not be seen. 
So much has been said for and against the 
thermometric detection of the presence of ice 
and icebergs, that I dislike to open the subject. 
Generally, if a ship is approaching ice or ice- 
bergs, repeated observations made by plunging 
a thermometer into the water alongside, or a 
bucketful from the sea, soon shows the fact by 
decreasing temperature. ‘These observations 
are more valuable in the summer than in the 
winter months, and also the farther south the 
SCIENCE. 
539 
ice may be encountered, owing to the more 
rapid change in the observed temperatures 
under these circumstances; but as nearly all 
arctic navigation is performed in the brief 
summer of these regions, and as it is only in 
the lower latitudes that the nights at this time 
are sufficiently long to cause apprehension, 
these observations here become of more value 
than in true arctic navigation. In the winter 
season, if the temperature of the water falls as 
low as 34° F. from a previous higher standard, 
it may reasonably be inferred that ice is not 
much farther away than half a mile: 42° F. 
shows about the same distance in the sum- 
mer, the thermometer falling rapidly as the 
vessel approaches. However, the thermometer 
shows a higher temperature in deep than in the 
shallow water on banks, shoals, and near the 
coast-line, often falling from 2° to 6° F. as 
the latter are approached. But a good chart 
and a fair degree of accuracy in dead reckoning 
will avoid confounding this with the decrease 
due to approaching ice. In the case of an 
iceberg stranded in a current, it is evident that 
even this valuable sign will fail on the current- 
washed side; so that when a vessel is running 
with an ocean-current where a berg is liable to 
ground, or where, from its great depth, the 
berg is subject to some more powerful under- 
current than exists on the surface, the only 
safeguard is in a vigilant lookout. A sailing- 
vessel, especially if she be small, should never 
approach an iceberg too closely, if there is 
any danger of becoming becalmed, especially 
in warm waters; as their disintegration, if of 
a colossal nature, is sufficient to throw quite a 
large ship on her beam ends, if taken at a dis- 
advantage. Sir John Franklin had the ship’s 
pinnace of the Trent thrown ninety-eight feet 
by the disruption of an iceberg about half a mile 
distant, which so completely stove the craft, 
that they were forced to a very annoying delay 
to repair it before they could return to the 
ship. This rupture had been determined by 
the firing of a musket by one of the party. 
Even if there be a good wind, there is some 
danger in running under the lee of a large berg, 
the eddying of the wind forcing a ship on the 
ice, while if too near by, sailer or steamer, it 
is not impossible that their keel might meet 
one of the newly ‘ calved’ icebergs that occa- 
sionly come boiling up from a great depth; in 
which case shipwreck would be almost inevi- 
table to a ship taken at such a disadvantage. 
Before discussing arctic navigation, as con- 
fined to the arctic region, something should be 
said regarding the variation of season. Nothing 
is more favorable to ice-navigation than a propi- 
