Outlines of a mechanical theory of storms, containing the true law of lunar influence, with practical instructions to the navigator, to enable him approximately to calculate the co by Bassnett Thomas b. 1808

Author:Bassnett, Thomas, b. 1808
Language: eng
Format: epub
Tags: Weather
Publisher: New York, D. Appleton & company
Published: 1854-03-25T05:00:00+00:00

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Fimba; me men TOTfiai penod: it 2k m is 23C6S91 meema* and iw i lA ; iJt a i « rf T.3SL7SULX s ta* ace en* aroott describes m me send = 3325.IT3SI feet* the iiyiww ot wbica di»id«£ by iie JTjmwtm or jag «ak» pvs Ike &K of tfee moo* from sbt sav^eic or rased sat of 1 110tfm-3«S7«*44

249898474* Tbift fraction isy however, too snail, as tbe

v

of the son diminishes the attraction of the earth on the moon, in the ratio of 178} J to 177} J. So that we must increase the fall of the moon in the ratio of 711 to 715, and hence the true fall of the moon from the tangent of her orbit becomes 0.00451 feet per second.

We have found the fall of a body at the surface of the earth, considered as a sphere, 16.1067 feet per second, and ihe force of gravity diminishes as the squares of the distances increases. The polar diameter of the earth is set down as 7899.170 miles, and the equatorial diameter 7925.648 miles; therefore, the mean diameter is 7916.189 miles.* So that, reckoning in 'mean radii of the earth, the moon's distance is 59.787925, which squared, is equal to 8574.595975805625. At one mean radius distance, that is, at the surface, the force of gravity, or fall per second, is as above, 16.1067 feet Divide this by the

1 /» 1 f\fth

square of the distance, it is ntf . A ^' nH ^^^ aex ^ = 0.0045058 * 3574.595975805625

feet for the force of gravity at the moon. But, from the preceding calculation, it appears, that the moon only falls 0.0044510 feet in a second, showing a deficiency of fad part of the principal force that retains the moon in her orbit, being more than double the whole disturbing power of the sun, which is only T^th of the earth's gravity at the moon; yet, on this T } T th depends the revolution of the lunar apogee and nodes, and all those variations which clothe the lunar theory with such formidable difficulties. The moon's mass cannot be less than fa, and if we consider it greater, as it no doubt is, the results obtained will be still more discrepant Much of this discrepancy is owing to the expulsive power of the radial stream of the terral vortex; yet, it may be suspected that the effect is too great to be attributed to this, and, for this

* The real diameter of the earth in that latitude, whose sine is one-third, is a little greater than this; bat the true mean is more favorable for the Newtonian law.

reason, we have suggested that the fused matter of the moon's centre may not gravitate with the same force as the exterior parts, and thus contribute to increase the discrepancy.

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