The Astronomical Observatories of Jai Singh c6.s1.t1.10

c6.s1.t1.10

Temporal hours.—The temporal or unequal or planetary hour lines are shown in figures 17 and 18, and in plate V by the broken lines *t*₁, *t*₂, etc.³ They divide the time between sun-rise and sunset into twelve equal portions and therefore vary in length from day to day. These divisions of time gradually fell into disuse (see page 87), and equal or equinoctial hours were introduced. These are shown in figures 18 (but not in figure 17) and in plate V they are marked *e*₁, *e*₂, etc.