or SEXAGESIMAL Fractions, fractions whose denominators proceed in a sexagecimal ratio; that is, a prime, or the first minute, \( \frac{1}{60} \); a second \( \frac{1}{3600} \); a third \( \frac{1}{216000} \). Anciently, there were no other than sexagimals used in astronomy; and they are still retained in many cases, though decimal arithmetic begins to grow in use now in astronomical calculations. In these fractions, which some call astronomical fractions, the denominator being always 60, or a multiple thereof, is usually omitted, and the numerator only written down: thus, 4°, 59', 32", 50", 16", is to be read, 4 degrees, 59 minutes, 32 seconds, 50 thirds, 16 fourths, &c.