. The encyclopædia of geography: comprising a complete description of the earth, physical, statistical, civil, and political. O P, to meet o s in A. Then, because O S, o s, areparallel (the distance of the star S being regarded as infinite), the angles O A o, A O S areequal; and, because O P o is the exterior angle of the triangle o A P, it is equal to tlie sumof the two interior and opposite angles A o P, o A P. Wherefore the angle O P o is equalto the sum of the angles A o P, P O S; that is, the angle subtended at the planet by thechord of the terrestrial arc intercepted between the points o
. The encyclopædia of geography: comprising a complete description of the earth, physical, statistical, civil, and political. O P, to meet o s in A. Then, because O S, o s, areparallel (the distance of the star S being regarded as infinite), the angles O A o, A O S areequal; and, because O P o is the exterior angle of the triangle o A P, it is equal to tlie sumof the two interior and opposite angles A o P, o A P. Wherefore the angle O P o is equalto the sum of the angles A o P, P O S; that is, the angle subtended at the planet by thechord of the terrestrial arc intercepted between the points of observation, is equal to the sumof the apparent distances of the planet from the star, provided the planet is seen (as we havehere supposed) on opposite sides of the star by the two observers. If the star is seen on thesame side by both, the angle at the planet will then be equal to the difference of the appa-rent distances. If the observers are so situated that P O, P o (fig. 17) are tangents to the circle O E o at thepoints O and o, the angle O P o will be the angle subtended by the disc of the earth at the
Size: 1505px × 1659px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, bookpublisherphiladelphialeaand
