Health without physic, or, Cordials for youth, manhood, and old age : including maxims, moral and facetious; for the prevention of disease, and the attainment of a long and vigorous life / by an old physician [pseud.].

  • Alcott, William A. (William Andrus), 1798-1859.
Date:
1830
Catalogue details

Licence: Public Domain Mark

Credit: Health without physic, or, Cordials for youth, manhood, and old age : including maxims, moral and facetious; for the prevention of disease, and the attainment of a long and vigorous life / by an old physician [pseud.]. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    tions on the sun's diameter, which is found to be con- siderably larger in winter than in summer, being largest of all when the sun is in perigee, about the 30th of December ; and smallest of all when he is in apogee, about the 30th of June :* whereas, if the orbit were circular, the sun's diameter would be always the same Hence, the earth being nearer the sun in winter than in summer, and its velocity, as well as that of the planets, varying according to their distances from the sun ; the winter half year is shorter than the summer half year—the former consisting of 178J days nearly, and the latter of 186'i days, making a difference of about eight days.-f- To exemplify this, let Fig. 2, Plate 2, represent an ellipsis, A C is called its transverse diameter, and B D its conjugate. F and S are its foci, which are situated at the distance A O (half of the transverse diameter), from the points B and D, the ends of the conjugate. If A B C D represent four different situations of the earth, or of any other planet in its orbit, it will appear very evident that its distance from the sun is variable. When it is at the point C, or in its perihelion, it will be considerably nearer the sun than when at A, or in its aphelion; and one half of its orbit may be plainly seen to be greater than the other half. The difference be- tween the centre of the ellipsis O, and the sun's place S, is called the eccentricity of the planet's or- bit; which, in the earth, amounts to about 1,590,000 * See Laws of Planetary Motion. t From the vernal to the autumnal equinox, in 1801, was 186 days, 11 hours, 34 minutes; from the autumnal to the vernal equi- nox, 178 days, la hours, 17 minutes.