396 POPULAR SCIJENCE MONTHLY. 



ORIGrN' OF A:N'CIE]STT niXDU ASTRONOMY. 



By the Count GOBLET D'ALVIELLA. 



IT is manifest tliat India is indebted for some of its astronomy to 

 the Greeks. Not that it had not astronomy and astronomers 

 from an epoch anterior to the invasion of Alexander. It had, in 

 fact, been necessary to make "observations of the heavens in order to 

 fix a calendar that would enable the sacrifices of the Yedic ritual in 

 connection with the return of the seasons and the revolutions of the 

 stars to be celebrated at the right dates. Further, the belief in as- 

 trology, or the influence exercised by the movements of the planets 

 on phj^sical phenomena and all the events of human life, would lead, 

 in India as elsewhere, to the observation and anticipation of every- 

 thing relating to the conjunction and opposition of the heavenly 

 bodies. 



The E-ig-Yeda has allusions to the phases and stations of the 

 moon. The stations {nakshatras) consisted, according to a tradition 

 preserved by the Brahmans, of twenty-seven constellations (after- 

 ward twenty-eight) which the moon was supposed to traverse suc- 

 cessively in the course of its sidereal revolution. A lunar zodiac 

 and a primary division of time into months were thus obtained. The 

 moon, moreover, bears in the Yeda the name of month-maker (mdsa- 

 Jcrit). Each station was assigned a uniform length of 13° 20' on 

 the ecliptic, and a denomination, generally derived from mythology. 

 The month, in turn, took its name from the constellation that had 

 the honor of harboring the moon. Manon and the Djyotisha (a 

 special treatise included among the Yedangas, or commentaries on 

 the Yedas) tell us that the year was composed of twelve months, 

 the month of thirty days, the day of thirty hours, the hour of 

 forty-eight minutes, all strictly sexagesimal subdivisions, like our 

 own measures of time. The Djyotisha also teaches the art of con- 

 structing a clepsydra, or water-clock. 



The adjustment of the solar year to correspond with the lunar 

 year and of the two with the civil year dates from this period. The 

 month was still composed of thirty days, but the solar years were 

 grouped into quinquennial periods, in the middle and at the end of 

 which the lunar month was doubled. Combining these quinquen- 

 nial periods with the revolutions of the planet Brihaspati (Jupiter), 

 which was calculated as occupying about twelve years, the Indian 

 astronomers computed an astronomical cycle of sixty solar years. 

 As the same cycle is found with the Chaldeans, Avhere, according to 

 ]3erosus, it was called the Sossos, we have to inquire how far Brah- 

 manic astronomy was influenced by the systems which were origi- 



