New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1873-09-20

| ont It il then tuDo coh1'iins Nv oo'' "
bHlb oreosote and water, above TINS mercuIy' anu
| above this little else than air. 1t is now evident
that "a the LIQUID in the large bulb expands with
beot II will as it rises in the tube, force the column
| Of mercury upward, and both the lower and the
INNER end of the column Of mercury will indicate by
| their position the amount of expansion. When the
liouid in the bulb contracts with cold, the column
of mercury will follow it toward the large bulb, and
the amount of tho contraction be indicated at both
ends of the mercury by its position. On the mer-
curry of each end of it, in the tube. rests small rod
| of steel which serves as en- index, around which
hair is twisted which acts a spring, and holds the
steel rod index in any position until the mercury
pushes it out of place and thus it keeps record of
the change of temperature Let us suppose that on
both sides this thermometer hanging in the cabin of
the steamboat, marked ESQ., the indexes just touch
ing the mercury. When the instrument has been
plunged into ice-water, the heat index still marks
65o, the mercury having simply fallen away from it
| but the index on the "cold" side las gone up to
freezing point Now if the thermometer is again
hung in the cabin, the mercury on the "heat" side
rises again to the 60 of the index and falls on the
"cold side to ESQ., But the index of the cold side
still remains at freezing point, and tells the story of
| the submersion.
So far this is "Six's sef-regstering thermometer"
Great numbers of records of deep sea temperatures
| had been procured by its means but it was found
that the results largely ytiated by the pressure
! of great depths of water. The glass OF which the
| bulb was made was of different thickness and quail
ity in different instruments, and no ratio Oh tne va
ration with which the glass yielded TO the PesSafe
Guilty was obviated by the Miller Casella modhca
tom This consists in inclosing the large pup III
outer shell partly filled with alcohol when yleIGs
so that the bulb within is not sensbly compressed I'D
| the deepest waters The present instrument is OK
ceedingly trustworthy, and it has already demon,
strated the great iDaccuracy OF previous IecoIus %
shown that much of the work i'll old localities needs
entire revision. 1t should be added that the scare
of the instrument is made of enameied glass ana tne
frame of hard rubber An OUTSIDE cyHnuIcai J'So
protects the whole from injury in case 1t should De
dragged over rocky bottom.
| PECULIARITIEs OF TEMPERATURE.
Soundings specific gravity. and chemical consti-
tuition. and temperatures though obtained by three
different instruments are nearly related in results
and it is not easy to say which of these classes OF OBJ
servations are most valuable. English authorities
aver that the contents of the water-bottle them
selves constitute nfallible index of the amount
Of animal life on sea bottoms. DR.. Carpenter says,
respecting an expedition off the Irish coast, the
ANALYST yentured to predict whether the collection
would be good or not before the dredge came to the
surface drawing his inference from the results of
his analyses of the gases of the bottom water. In
each case his prediction was justified by the result
The determination of bottom temperatures is of still
greater importance. The force direction. and char
acter of ocean currents such those which led to
! the wreck of the Atlantic, in large measure as
certained from thermometric observations Our
knowledge of the habits of marine animals and of
the best methods of increasing the supply of food
from our fisheries will be sadly defective without
precise information to the temperatures conducive
to their we'll being. very cold spell" occurring
at low tide is said in instance to have killed the
tautog in such numbers that hundreds of tons were
thrown ashore at Block Island and along the south
ern shores of Rhode Island and Massachusetts,
Before we can use the self-registenng thermome
ter on the Blue Light the indexes must be set. If
the instrument has been down at sea bottom the in
dex on the cold side is probably left up freez-
| ing point If afterward the thermometer was hang
ing in the cabin, the index on the heat side is
probably above the point where we shall want it to
be- for we begin by recording the temperature of the
surface water keeping the thermometer in a bucket
of it on deck and renewing the water from time to
time especially when change the locality Of our
Investigations The indexes are drawn down to the
| level of the mercury by means of magnet Rather
too frequently an index is apt to stick so tightly in
| the place in the tube to which it has been lifted
that the magnet ordinarily relied upon fails to
| it, and then other and stronger magnets must be
used to bulge it, Occasionally an index seems to be
magnetic persuasion entirely. This appears to me
one of the most frequent troubles with what is
| otherwise q most serviceable instrument. The
amount of coaxing which some of those indexes re-
quire is positively discouraging.
chief point to ascertain and record is the differ
ence between surface and bottom temperatures as
well as that between the atmosphere and the water.
The depths of usually very cold, approx
mating freezing point. The temperature of surface
| water is intermediate between that of the bottom
and the air. and in observations in this vicinity va
res from SO to ESQ. averaging 100 below the tenn
perature of the air. though in one instance 22o and
| vet been ascertaned between air and surface tenn
peratures. The records of bottom temperature indi
cate in general fall of temperature with increasing
depth until freezing point is approximated; but this
rule is much modified by the influences of locality;
sheltered sounds and bays being usually for
the same depth than the open ocean. The following
are some of the records:
| In QuObog Bay at fathoms, and in the sounds Of
Casoo Bay at So fathom the index showed $50 to 55to
In being only lio below surface temperature.
At III fathoms thermometer stood 47o at H. blo
at IS and It, 1870 at II and 2 47o at 81 asp at & 49,
Outside OF the shelter Of projecting land the tempera-
at IL to fahoms was generally 46' TO asp but In
one 50So which within less than 40 OF that
the surface water at 10 to "a fathoms the records
show 49, to tS; at 49, Az at 90 "a as az - Stp 70
a wide field for investigation TO determine the varying
causes which these records indicate Our knowledge Of
the waters of our coast is yet in its infancy.