. Mathematics, compiled from the best authors and intended to be the text-book of the course of private lectures on these sciences in the University at Cambridge [microform]. other pole, describea circle EQ, for the equator, and divide it into 24 equalparts for hours. These are to be numbered from east towest ; with six on the top, the hours of the forenoon abovethe equator, and those of the afternoon below it. Note. The sphere is to be placed so, that the elevationof the pole P may be equal to the latitude, or the axis par-allel to the earths axis, and the line, or meridian, APB inthe meridia
. Mathematics, compiled from the best authors and intended to be the text-book of the course of private lectures on these sciences in the University at Cambridge [microform]. other pole, describea circle EQ, for the equator, and divide it into 24 equalparts for hours. These are to be numbered from east towest ; with six on the top, the hours of the forenoon abovethe equator, and those of the afternoon below it. Note. The sphere is to be placed so, that the elevationof the pole P may be equal to the latitude, or the axis par-allel to the earths axis, and the line, or meridian, APB inthe meridian of the place. Then the circle bounding the il-luminated hemisphere shows the time at its intersectionwith the equator EQ. DIALING. 365 PROBLEM XVIII. To find the hour of the night by a sun dial, -when the moon shines on it. Find the moons age, or the number of days elapsedsince a change or full. Add | of this number, being thetime in hours corresponding to the moons distance fromthe sun, to the time shown by the moon on the dial, andthe sum, or its excess above 12, when it exceeds thai num-ber, is the time required. PROBLEM xix. To draw an equinoctial moon dial. Ml. With radii of convenient length, describe two concen-tric circles A, B ; divide the circumference of each into29 equal parts, and join the corresponding poinds. Onanother plane, which is circular, and its radius equal to CB, 366 MATHEMATICS. describe an equinoctial solar dial, as, for example, the supe-rior one D. Note. This dial has the same stile in the centre C, andits plane is set in the same position, as the equinoctial solardial. The circle D is to be put on B concentric with it, andmoveable about the centre. Then the XII oclock line onD is to be set to the moons age on the plane AB. ?*?; & y% * ae «*: :*: sc ?*•: & ac .*; ;*: SPHERIC GEOMETRY DEFINITIONS. : PKERIC Geometry is the doctrine of theSphere, particularly of the circles described on it ; with themethod of projecting the same on a plane, an
Size: 1704px × 1466px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1800, bookidmathematicsc, bookyear1808
