Report of the Committee of Physics and Meteorology of the Royal Society Relative to the Observations to Be Made in the Antarctic Expedition and in the Magnetic Observatories (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1840 Excerpt: ...days of the new and full moon;--as it must be borne in mind, that in what concerns the great meteorological questions on which the most interesting features of the subject depend, the night is quite as important as the day, and has been hitherto far too much neglected. Whatever hours, however, may be selected for the regular series of observations, the greatest care should be taken not to insert in the register anything deduced by interpolation from observations made at other hours, or anything in short but what has been actually observed. It is much to be wished that occasional observations may be made under remarkable circumstances, such as during great rises or great falls of the barometer, at the period of great storms, earthquakes, &c.; but such observations should be registered apart. The barometer should be placed in an apartment subject to as little variation of temperature as possible, and in a good light; and to facilitate night observations, an arrangement should be made for placing behind it a light screened by a sheet of white paper, or other diaphanous substance. Great care should be taken to fix it in a perpendicular position by the plumb-line. Its height must be carefully ascertained above some permanent and easily-recoverable mark, either in the building in which it is situated, or in some more permanent building, or rock, in its immediate vicinity; and no pains should be spared to ascertain the relation which such mark may bear to the level of high and of low water at spring tides, and ultimately to the mean level of the sea. Changes in the adjustments of meteorological instruments should be most carefully avoided; but whenever any alterations may be absolutely necessary, they should be made with all deliberation, scrupulously noticed ...