Celestial and Terrejlrial Globes. 311

on the oriental or ascending side, and ©PG,i P G, on the occidental or descending side.

In either of these four triangles there aresufficient data to find what is required inthis problem. In the triangles ©PB, ®PG>are given, 0 P in both, the lun’s distancefrom the pole, P B, equal to P G, the dis-tance of the vertex from the pole, which isalways equal to the complement of the la-titude, with the sides 0 B, © G, each equalto 90 degrees.

To find the angle PB©, or P G©, thesun's amplitude from the north, when risingor setting) and the angle ©PB,.or ©PG,the time before noon. But as the two lastmentioned angles are obtuse, we chuse toresolve this problem by one of the two lessertriangles P B i, PGi, each of them beingright angled at i, in which are given, P i,the reflection, 15 0 33b equal to the decli-nation, BP, equal to P G, 38° 28b the dis-tance of the pole from the vertex.

To find the angle PB i, or PGi, thecomplement of ©Bi, or ©Gi, the sun’samplitude at rising or setting from the eastor west, and the angle i P B, equal to theangle i P G, which are formed between theX 4 fun's