Guy's Elements of astronomy : and an abridgment of Keith's New treastise on the use of the globes . J^r p<^t. ffeh^rrritTir r/7/i/ Oeore^rhfj- Lrifte/rturff. UMBRA AND PEjVUMBRA, IN ECLIPSES. 83 penumbra, P U the line described by the centres ofthe moons umbra and penumbra at the earth; N themoons node; E the earths centre; ^^ n the moonspenumbra; u the umbra. Then in the first position,the penumbra p n just passes by the earth, without fall-ing upon it, and therefore there will be no eclipse. Inthe second position, the penumbra p n fails upon theearth, but the umbra u does not. In the thir
Guy's Elements of astronomy : and an abridgment of Keith's New treastise on the use of the globes . J^r p<^t. ffeh^rrritTir r/7/i/ Oeore^rhfj- Lrifte/rturff. UMBRA AND PEjVUMBRA, IN ECLIPSES. 83 penumbra, P U the line described by the centres ofthe moons umbra and penumbra at the earth; N themoons node; E the earths centre; ^^ n the moonspenumbra; u the umbra. Then in the first position,the penumbra p n just passes by the earth, without fall-ing upon it, and therefore there will be no eclipse. Inthe second position, the penumbra p n fails upon theearth, but the umbra u does not. In the third position,both the penumbra p n and the mubra u fall upon theearth; therefore, Vi^here the penumbra falls there will beB, partial eclipse, and where the umbra falls there willbe a total eclipse; and to the other parts of the earththere will be no eclipse. As a description of a total eclipse of the sun may be interesting to theyoung reader, we select a few particulars of that which happened April22d, 1715. Captain Stannyan, of Berne, in Switzerland, says, the sunwas totally dark for four minutes and a half; that a fixed star, and planet,appeared very bri
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectastronomy, bookyear18
