Meteorological observations and essays / By John Dalton.

  • John Dalton
Date:
1834
Catalogue details

Licence: Public Domain Mark

Credit: Meteorological observations and essays / By John Dalton. Source: Wellcome Collection.

    203/280 (page 177)
    SPRING TIDES, NEAP TIDES. No. of Aurore 1444 1072 Ratio 4. 3, nearly, which is favourable to the supposition. It may be objected, that as the latter division contains the whole of the second quarter of the moon, when its light is strong, and when it is above the horizon all the time there is to observe the aurora, the phenomenon is not noticed as often as it takes place in that quarter.—This may be right, but it should be observed, that the last quarter of the moon, which is wholly exempt from this ob- jection, falls in the same division; and both the first and third quarters, constituting the other division, are in part liable to the same objection. However, in order to determine whether this objection is of such import as to counterbalance the apparent conclusion contained above, it may be proper to find and compare the number of observations in the first and last quarters only. This being done, on the principle above used, the numbers stand, First quarter, or spring tides. Last quarter, or neap tides. 935 81 From which it appears the phenomenon is ob- served more frequently in the first quarter of the moon, though liable in part to the above objection, than in the last quarter, which is wholly free from it. Presuming then from what is done above, that AA