50 A Letter from Archdeacon Pratt. [No. 1, 



By the Nautical Almanac for 1859, the position of Eegulus is 

 given as follows : — 



Eight ascension, January 1st, 1859, ... ... 107j. 0m. 53s. 



North declination, ditto, 12° 39' 12."7. 



From this I obtain, by spherical trigonometry, the following re- 

 sult :— 



Longitude of Eegulus, January 1st, 3859, ... 147° 52' 30". 



Hence Eegulus was east of the Summer Solstice at that date by 

 57° 52' 30". The Summer Solstice had, therefore, retrograded 

 through 42° 12' 30" = 42°.208 since the epoch of the Vedas. As 

 the equinoxes and solstices move backward on the ecliptic at the 

 rate of 1° in 72 years, it must have occupied 72 X 42°.208 = 3039 

 years to effect this change. 



Hence the age of the Vedas was 3039 on 1st January, 1859 ; or 

 their date is 1181 B. C, that is, the early part of the twelfth century 

 before the Christian era. 



This differs from Mr. Colebrooke's result : he makes it the 14th 

 century. Two more degrees of precessional motion would lead to 

 this ; but where he gets these from, I do not know, unless it be by 

 taking the constellations loosely, instead of the exact lunar mansions. 

 Thus Dhanishtha being taken to be the lunar mansion above which 

 the Dolphin occurs, it is possible that he may have considered the 

 first star in the constellation Dolphin to be the " beginning of Dha- 

 nishtha" alluded to in the Jyotish ; and similarly he may have taken 

 a star in the middle of Hydra's head to represent the " middle of 

 A'slesh'a." But even this supposition will not carry us into the 14th 

 century. If we take the first star c in Dolphin and the opposite star 

 £ in Hj^draVHead to be the solstitial points, the precessional motion 

 will only be about 40' more than above, and the date will be B. C. 

 1229 or late in the 13th century. But then £ is not in the middle 

 of Hydra's head ; it is about 2° east of it ; and therefore I have no 

 doubt the lunar mansion, and not the constellation, is what the 

 Jyotish refers to, and the early part of the 12th century is the 



correct result. 

 \ I am, your's very truly, 



John H. Pratt. 

 To Professor Cowell, 



Secretary of the Asiatic Society of Bengal. 



