EQUIPMENT. 
Sir William Thomson would find it difficult indeed to recog- 
nize his original machine as now used on board the “ Blake,” 
with the modifications introduced by Lieutenant-Commander 
Sigsbee. During the four years of his command, the latter 
ran no less than 12,766 nautical miles of sounding-lines, with 
the necessary serial lines of temperatures. As the result of his 
magnificent work, the Coast Survey is publishing a hydro- 
graphic chart of the Gulf of Mexico, not merely unequalled 
for its accuracy, but unique as the first chart of any extent 
which carries the littoral hydrography to great depths. 
The depth having been obtained, the thermometer attached 
is drawn up, record the bottom tem- 
, [ҮҮ ТҮ | 
perature. The deep-sea thermometer | | | «M 
pi и, | 
(Fig. 11.) It is a maximum and mini- | Ve 
mum thermometer. Its modified form ul bU m 
M y in 
and constructed by Casella. It con- 4 | yl \\ i 
sists of a U-shaped tube, the lower Qi e| M 
minating on the one side in a large bulb filled Из 
with a mixture of creosote and water, while the ||| 
part with the same liquid. А steel index, kept || - 
in place by a horse-hair spring, is placed in each 
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we \ 
to the stray line will, if allowed to remain long enough before it 
VM 
used is known as the Miller-Casella. | | 
(HM 
was suggested by Professor Miller, Il 
Ma 
part of which is filled with mercury, the U ter- wE jp 
small bulb of the other branch is filled only in 
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El 
limb. The indications are given by the expan- |. 10 E] 
sion and contraction of the mixture in the large ||| ET 
bulb, which allows the mercury either to recede well eg 
from the large bulb or to flow towards it; the Е Е 
index is carried on either side by the movement lur. | F 
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of the mercury, and on the retreat of the mer- 
cury the index remains at the highest р | 
point reached. - То prevent the:effects | \\ | jl 
of the enormous pressures to which 
these thermometers are subject, the 
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ment ТШШ 
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inner large bulb is protected by an 
outer bulb nearly filled with alcohol, 
Fig. 11. — Miller-Casella Ther- 
mometer. Half size. 
