"This arose from the following cause: They came from the East before the supposition that the precession took place a degree in about 60 years, and 1824 years in a sign had been discovered to be erroneous; and as they supposed the Neros made a correct cycle in 608 years, and believed the precessional cycle to be completed in 21,888, they of course made their ages into twelve. As both numbers were erroneous, they would not long answer their intended purpose, and their meaning was soon lost, though the sacred periods of twelve ages and of 608 remained." According to Hipparchus and Ptolemy, the equinoxes preceded at the rate of a degree in 100 years, or 36,000 hundred years in 360 degrees. This constituted a great year, at the end of which the regeneration of all things takes place. This is thought to be a remnant of the most ancient Hindoo speculations, and not the result of observation among the Greeks. Some time after the arrival of the sun in Aries, "at the vernal equinox, the Indians probably discovered their mistake, in giving about 60 years to a degree; that they ought to give 50" to a year, about 72 years to a degree, and about 2160 years to a sign; and that the Luni-Solar cycle, called the Neros, did not require 608 years, but 600 years only, to complete its period. Hence arose the more perfect Neros." It is thought by various writers that the knowledge of the ancient Hindoos regarding the movements of the sun and moon in their cycles of nineteen and six hundred years--the Metonic cycle, and the Neros--proves that long before the birth of Hipparchus the length of the year was known with a degree of exactitude which that astronomer had not the means of determining. It is positively asserted by astronomers that at least twelve hundred years were required, "during which time the observations must have been taken with the greatest care and regularly recorded," to arrive at the knowledge necessary for the invention of the Neros, and that such observations would have been impossible without the aid of the telescope. On the subject of the great learning of an ancient race, Sir W. Drummond says: