6  "One day out of this long life of Brahma is called Kalpa; and a Kalpa is that portion of time which intervenes between one conjunction of all the planets on the horizon of Lanka, at the first point of Aries, and a subsequent similar conjunction.  A Kalpa embraces the reign of fourteen Manus, and their sandhies (intervals); each Manu lying between two sandhies.  Every Manu's rule contains seventy-one Maha Yugas,—each Maha Yuga consists of four Yugas, viz., Krita, Treta, Dwapara, and Kali; and the length of each of these four Yugas is respectively as the numbers, 4, 3, 2 and 1.
The number of sidereal years embraced in the foregoing different periods are as follows:
     Mortal years
360 days of mortals make a year     1
Krita Yuga contains     1,728,000
Treta Yuga contains      1,296,000
Dwapara Yuga contains      864,000
Kali Yuga contains     432,000
The total of the said four Yugas constitute a
Maha Yuga      4,320,000
Seventy-one of such Maha Yugas
     form the period of the reign of one Manu     306,720,000
The reign of 14 Manus embraces the duration
     of 994 Maha Yugas, which is equal to      4,294,080,000
Add Sandhis, i.e., intervals between the reign of each
     Manu, which amount to 6 Maha Yugas, equal to      25,920,000
The total of these reigns and interregnums of
     14 Manus, is 1,000 Maha Yugas, which constitute
     a Kalpa, i.e., one day of Brahma, equal to      4,320,000,000
As Brahma's night is of equal duration, one day
     and night of Brahma will contain     8,640,000,000
360 of such days and nights make one year
     of Brahma, equal to      3,110,400,000,000
100 of such years constitute the whole period
     of Brahma's age, i.e., Maha Kalpa     3,110,400,000,000
 
That these figures are not fanciful, but are founded upon astronomical facts, has been demonstrated by Mr. Davis, in an essay in the Asiatic Researches; and this receives further corroboration from the geological investigations and calculations made by Dr. Hunt, formerly President of the Anthropological Society, and also in some respects from the researches made by Professor Huxley.
 
Great as the period of the Maha Kalpa seems to be, we are assured that thousands and thousands of millions of such Maha Kalpas have passed, and as many more are yet to come.  (Vide Brahma-Vaivarta and Bhavishyre Puranas; and Linga Purana, ch. 171, verse 107, &c.) and this in plain language means that the Time past is infinite and the Time to come is equally infinite.  The Universe is formed, dissolved, and reproduced, in an indeterminate succession (Bhagavata-gita, VIII, 19)."—The Theosophist, Vol. VII, p. 115.