. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. EQUIPMENT. 15 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 lides 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
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. EQUIPMENT. 15 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 lides 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 to the stray line will, if allowed to remain long enough before it is drawn up, record the bottom tem- perature. The deep-sea thermometer used is known as the Miller-Casella. (Fig. 11.) It is a maximum and mini- mum thermometer. Its modified form was suggested by Professor Miller, and constructed by Casella. It con- sists of a U-shaped tube, the lower part of which is filled with mercury, the U ter- minating on the one side in a large bulb filled with a mixture of creosote and water, while the small bulb of the other branch is filled onlv in part with the same liquid. A steel index, kept in place by a horse-hair spring, is placed in each limb. The indications are given by the expan- sion and contraction of the mixture in the large bulb, which allows the mercury either to recede from the large bulb or to flow towards it; the index is carried on either side by the movement of the mercury, and on the retreat of the mer- cury the index remains at the highest point reached. To prevent the effects of the enormous pressures to which these thermometers are subject, the inner largfe bulb is protected by an o r J Fiff. 11. Miller-Casella Ther- outer bulb nearly filled with alcohol, mometer. Half Please note that the
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Keywords: ., bookauthorha, bookcentury1800, bookdecade1860, booksubjectzoology
