546 THE POPULAR SCIENCE MONTHLY. 



periods of sixty years we have to omit two years, one in the first cycle, 

 and the other in the third ; but in thirty cycles we have to omit 0*7 

 year X 30 = 21 years, while the preceding correction has omitted only 

 twenty years ; so a new suppression of a year has to be performed in 

 each series of thirty cycles. 



The Hindoos also employed ages in the computation of time, and 

 these, too, divided into periods of different durations. The present 

 age is the kali yuga, or the age of iron ; 4,985 years of it have already 

 passed, but its total duration is supposed to be 432,000 years. The 

 succession of the ages, counting back, is given as follows : 



Fourth age Kali yuga, age of iron, or of woe (the present age), to 

 be of 432,000 years. 



Third age Dvapara yuga, 864,000 years. 



Second age Treta yuga, or age of silver, 1,296,000 years. 



First age Krita yuga, age of gold, or of innocence, 1,728,000 years. 



These four ages form the maha yuga, or great age, of 4,320,000 

 years. The length of a patriarchate is seventy-one maha yugas, or 

 306,720,000 years, to which is added a twilight period of 1,728,000 

 years, making in all 308,448,000 years. Fourteen of these patriarchates, 

 augmented by a dawn of 1,728,000 years, gives 4,320,000,000 years, 

 which form a halpa, or the ceon of the Hindoo chronology. 



A kalpa is only a day in the life of Brahma, whose nights are also of 

 the same duration. Now, Brahma lives a hundred years of three hun- 

 dred and sixty days and three hundred and sixty nights. The present 

 epoch is the kali yuga of the twenty-seventh grand age of the seventh 

 patriarchate of the first seon of the second half of the life of Brahma, 

 who is now in his 155,521,972,848,985th spring. Yet the whole life of 

 Brahma is only a little longer than a single wink of Siva's eye ! 



The Greeks employed first two years of 12 months each consisting 

 of 30 days, and a third year of 13 months, giving an average of 370 

 days to the year ; then the cycle of 19 lunar years, with seven months 

 intercalated in each cycle to obtain 19 solar years. The months were 

 of 29 and 30 days, and the time was calculated by Olympiads, of four 

 years each. Afterward, Calippus introduced the cycle of Meton, 433 

 years b. c, shorter than the 19 solar years, in consequence of the sup- 

 pression of a day every 76 years. The era of the Olympiads goes 

 back to b. c. 776, at which time Corcebus obtained the prize in the 

 race, from and after which date the names of the victors were inscribed 

 on the official registers. 



The ancient Egyptians reckoned at first 12 months of 30 days, or 

 360 days ; but they afterward added five supplementary days. The 

 years were counted from the accession of the kings ; and the canon of 

 Ptolemy is a chronological table giving the changes of the reigns. 

 The same form of year was formerly in use among the Persians, with 

 the difference that they added the five supplementary days to the 

 eighth month instead of to the twelfth. Their months had particular 



