English
The European method re- quires that the motions be determined by two actual observations at least, and at a considerable distance of time : the Hindu, in artificiail systems, requires no such thing ; he makes use of but one observation, which is in the time of the observer : the other he Digitized by Google PREFACE, XV assumies; that is to say he assumes that the planets were in a line of mean conjunction at the beginning of the Kali Yuga, and from thence draws the motion that would give the position of the planet in his own time, agreeing with his observation. To make this matter plain, I will give an example. Suppose that in A.D. 939, at the end of the year 4040 of the KaliVuga, there were two astronomers making observations on the planet Venus at the same place, one being a European, the other a Hindu, and that they both found the place of the planet in the Hindu sphere to be then 2* 19^ 65' 12\ The Hindu astronomer says to the European : ** We must now find the mean annual motion that will give this position ; and observes, that at the beginning of the Kali Yuga, the planets were all in a line of mean conjunction in the beginning of the Hindu sphere ; consequently, that the mean annual motion of Venus, multiplied by 4040, the years then elapsed, must give the position, and therefore the mean motion must be=7*15''ll' 52*8; for if this quantity be multiplied by 4040, it will produce 2* 19'* 55' 12'." The European astronomer observes : * * We have agreed in the actual position of Venus at the end of the year 4040 of the Kali Yuga, because it depends on actual observation made now by both of us ; but the as- sumption that the planets were in a line of mean conjunction in the beginning of the Kali Yuga, I cannot admit to be true : for by our tables, which I b Digitized by Google XVI PREFACE. take to be perfectly correct, Venus^ was not in the position assumed by you, for ber Ipngitude then, was V 2° 43' 46"6 ; consequently the mean annual motion must be less tlian what you make it, and by my calculation comes out exactly 7* 15° ir23''635, which, if multiplied by 4040 years, we shall have . . . V 17° 11' 25"4 Add position of Venus at the epoch, 1 2 43 46 6 We get her mean longitude now, =2 19 55 12 " The Hindu astronomer replies: ** Yes, Master European, your mode may be true ; for we have no means of detecting its errors, since we had no ob- servations at the beginning of the KaliYuga: we can only say, that you take more trouble by adding the supposed position of Venus at tlie epoch than we do. , We manage it otherwise, as you see, by simply taking the mean motion such, that it gives us the position without any addition or subtraction, which labour we save." : The European astronomer says : *^ You certainly save both labour and time ; but still I do not ap- prove of your method, because it is incorrect : for though it gives the same longitude to the planet as mine does for this moment of time, yet it will not continue to do so for any length of time. For instance, next year there will be a difference be- tween us of 29''166, and it will for ever after con- tinue to increase at that rate yearly. But this is not all : .our great astronomers, who may live between Digitized by Google PREFACE. XVU eight and nine hundred years hence, will be de- ceived by the annual motions which you thjiis de- duce, some being greater, and others less than we give them, thereby, according to physical ideas, indicating great antiquity; so that your time will be thrown back between two and three thousand years." The Hindu sustrohomer replies: *' I am very glad to hear it ; I did not mean deception ; but since you will have it so, take it. I did not think the European astronomers to be such fools as to be de- ceived by our manner of deriving the mean motions." Thus I have endeavoured to show, in a familiar way, the Hindu method of deriving the mean an- nual motions, which being totally different from the European, renders the method of Bailly and others, of ascertaining the supposed antiquity of astronomi- cal tables from the quantity of the mean motions, as totally inapplicable. But it may be done, if we apply the principle upon which they have been derived ; otherwise not. Thuis, suppose we have the mfean annual motion of Venus as above given = T 15° ir 52''8, to find what year this motion corresponds to, that is, the year in which it would give the mean longitude of Venus corresponding to observation, the mean motion of Venus, according to Europeans, in the Hindu sphere, would be as above:^?' IS"" U' 23^635 Which taken ftom the fonner, 7 15 11 52 8 Leaves a remainder of . . 29165 Digitized by Google Xvni FREPACE. The position at the epoch of the Kali Yuga, ac- cording to Europeans = 1* 2"" 43' 46*6; divide the latter by the former, and we have ^^^^=4040, the year from the epoch v^hen it gives the position of Venus agreeing with observation. The reviewer says; '* The antiquity of it (the Suri/a Siddhantd), has been conceived to be very great, as it is reckoned the most ancient astrono- mical treatise of the Hindus; but, according to Mr. Bentley, that antiquity extends to no more remote period than the year 1068 of our era. The main argument oft which this determination is founded, seems to us subject to considerable diffi- culty. It supposes what is by no means certain, that the Hindu astronomers deduced the mean mo- tions of the planets from a comparison of a real ob- servation with one that was purely fictitious. This is no where proved by Mr. Bentley, though taken as the basis of all his computations." The asser- tion of the reviewer in thia instance is positively untrue; for I have shown, from the data given in the Surya Siddkanta itself, that all the mean motions and positions of the planets given by that work are expressly deduced from the assumption of the planets being all in a line of mean conjunction in the beginning of the Hindu sphere, at midnight, at the beginning of the Kali Yuga, and on the meridian of Lanka. These data are all derived from the work Digitized by Google PREFACE. XIX itself.^ and what will show it to be assumed, and not a real epoch of observation, is, that the vernal equinoctial point, or the beginning of Aries in the tropical sphere, was then assumed to be also in the same point with the planets, which we know could not have been the case ; for the sun's mean longi- tude in the European sphere at that moment was l(y V r r, and therefore 60 days short of the time : yet, notwithstanding all this apparent absurdity, it is the epoch from which not only the motions of the planets are reckoned and drawn, but also the pre- cession of the equinoxes. It is really ridiculous to see a man like the reviewer, who seems to know nothing whatever of the Hindu astronomy, talk on a subject he is unacquainted with, and pretend, with the utmost gravity, that the Hindus, like all other people, must have two or more observations made at a distance, from whence they drew the motions of the planets. They might have hundreds or thou- sands of observations in ancient times at a distance from each other, and draw the mean motions from thence for other books, but not for the artificial systems now in use, nor the Surya Siddhanta^ which is ^itirely on an artificial plan : and all those that are on an artificial plan have been introduced since A.D. 638, for the purpose of imposition, in order that their history and astronomy should be considered by the ignorant as excessively ancient ; in which impor Digitized by Google XX PREJ'ACE. sition tbey have certainly but too well succeeded. The example 1 have above given respecting Venus^ shows 1m)w the motions are deduced, the position in the astronomer's time being known from observa* tion : and it also shows, from the motion alone, how to determine the time to which it refers. They are the same as are given by the Smya Siddkanta. The Hindus have many astronomical books not on the artificial plan : they are, however, all modem, and do not fall within the scope of my observations, as they are hardly worth noticing. It is to the ex- posure of die impositions introduced by the artificial systems, that my whole attention has been princi- pally du^cted. Is it not most strange that Mr.