Annual report of the Department of Public Charities of the City of New York ... v.12, 1871, Τόμος 12

Εξώφυλλο
Department of Public Welfare, 1871
 

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Σελίδα 258 - From this point the mean depth across the ocean may be estimated at about 2,400 fathoms, but from this there are two striking departures — first a depression, the depth of which is 3,100 fathoms, and second, an elevation at which the soundings are only 1,900, — the general result of this being a wide and deep trough on the African side, and a narrower and shallower trough on the American. It may be that this peculiarity is a result of the river distribution on the two continents respectively,...
Σελίδα 264 - Though the quantity of organic substance diminished as the stratum under examination was deeper, there still remained a visible amount in the water of four hundred or five hundred fathoms. It is probable, therefore, that even at the bottom of the ocean such organic substance may exist, not only in solution affording nutriment to animals inhabiting those dark abysses, as Professor Wyville Thompson has suggested, but also in the solid state. Plants of course cannot grow there, on account of the absence...
Σελίδα 243 - Giraud, to obtain a series of soundings on the line of or near the equator, from the coast of Africa to the mouth of the Amazon, to observe the set of the surface currents and the temperature of the water at various depths.
Σελίδα 264 - It needed no special proof that organic matter was present in every one of these samples, for the clearest of them contained shreddy and flocculent material, some of them quantities of seaweed in various stages of decomposition. With these vegetable substances were the remains of minute marine animals. As bearing upon this subject, I found, on incinerating the solid residue of a sample of water taken from two hundred fathoms, that the organic and volatile material was not less than eleven per cent,...
Σελίδα 262 - ... elevation about the meridian of 45° west longitude, as though the contour of the bottom was not without influence on the physical state of the water above it. The general conclusion which may be drawn from these results as to temperatures and specific gravities is, that there exists all over the bottom of the tropical Atlantic and Caribbean Sea a stratum of cold water — cold, since its temperature is below 50°. This is the conclusion to which Dr. Carpenter has come, as respects the Atlantic...
Σελίδα 263 - ... reasons I did not consider it necessary to make an analysis of the gases afforded by these specimens. Dr. Carpenter, from his experiments, concluded that when freshly-drawn water is tested, the proportion of carbonic acid increases as the stratum of water is from deeper sources. I made some examinations of the organic matter contained in these waters, both by incinerating the solid residue and by the permanganate test. It has been customary to divide such organic ingredients into two groups,...
Σελίδα 255 - ... variations must be determined in the case of each individual instrument, for the amount of this error will vary with the varying thickness of the glass, its form, and its power of resisting compression. In the experiments made by Dr. Miller on self-registering thermometers for deep sea sounding, published in the report of the Meteorological Committee of the Royal Society for 1869, it is shown that certain unprotected thermometers submitted to a pressure of two and one half tons per square inch...
Σελίδα 260 - ... many cases. This decline of temperature increases as the depth increases, one observation giving an additional fall of four degrees at an additional depth of 200 fathoms. It is not, however, intended to affirm that the mass of cold water is restricted to these deep troughs, since even in the "West India seas, at similar depths, low temperatures are observed, and this, though the heat of the surface-water has become very much higher. In those seas, while the surface temperature was 84°, the thermometer,...
Σελίδα 262 - Atlantic in higher north latititdes ; and in this important particular the cruise of the Mercury must be considered as offering confirmatory proofs of the correctness of the deductions drawn from the cruises of the Lightning and Porcupine. There are reasons for supposing that, so far from this water being stagnant, its whole mass has a motion toward the Equator, whilst the surface-waters in their turn have a general movement in the opposite direction. As the samples of water had already been kept...
Σελίδα 258 - ... in question. However this may be, it is doubtless through these deep troughs that much of the cold water of the North Polar current finds its way. In accordance with this, we perceive, on examining the temperature of the water, after the African verge of the greater or eastern sea trough is reached, that there is a difference in temperature between the surface and that at a depth of \ \ not more than two hundred fathoms, exceeding twenty-five degrees in many eases.

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