of Eclipses, und Especially of La Dcljp8e8 143 CHAPTER IV OF ECLIPSES, AND ESPECIALLY OF LUNAR ECLIPSES CONTE8 1, dimensions of the sun and moop 2-8, measurement of their pparent dimensions; 4-6, measurement of the oarth' shadow: 6, conditions he g: Yence of an eepae; 1-४, a«innent of longitude of :e title of conjunctio of of opposition 9, enumse o lp<e$ 10-11, to determino whether there will be \ > 8e. an ]he aः unt o¢ %fauration; 12:15, to find } Elhe time of du£B १on of the e:lapx a]f the of onal obscursion ; 186-17 to ascertai। the Lines funtry | B"paration. end in a tot.. 8। of i 'sion and ebuergeTE; 18-21, | d«z। }९ ।। १mount of obscura ot a given tinue 2-98 . to find It ihnue corresponding to a |': amount of obscuratio : 9-25, Insureof the d flection of the elaptir, at the |boint occupied y the elped body, from ena An yes link ; 2 cen1letion f the scale of project tion for doicrcnce of itude. 1. The diameter of the sun's disk is six thousand fiv hundred yojanas ; of the moon's, four hundred and eighty We shall see, in connection with the next passng', |hnt the diameters of the sun and moon, as thus stater, are subject to a curiou modification dependent upon and representing the greater or less distince of those bodies from the earth; so that, in a certain sense, we have here only their Imean diameters. These represent, however, in the Hindu theory. --which aftects to reject the supposition of other orbits than such as are circulaz, and described at equal distances about the ९rth---the true absolute dimensions of the sun and moon. Of the two, only that for the moon is obtained by a legitimato proceRE, or presents ony nenr approximation to the truth. The diameter of the earth being, ns stated above (i. [9), 1600 y०janas, that of the moon. 480 yojnnas is .3 of it: while the true value of the nOb 's dinmete " in terms of the earth's is .2716, or only about a tenth less. An estimate ko nearly orfect supposes, of course, an equally correct determination of the moon's horizontn parallax, distance from the earth, and mean apparent diannote. The Hindu valuation of the parallax may be deduced from the value given just below (v. B), of a minute on the moom's orbit, as 15 yojana. Since the rmoon's horizontal prollnx is |ual to { n«le subtended at her centre by the earth's radiuk, and Rineo, at the look13 mean distance, 1/ of arc equals 15 yojanas, and the orh's Indint8, 80 yojanas, would accordingly subtend an angle of 38 20–the latter ongle, 53 20, is, according to the system of the stry-Siddhanta, mom's the parallax, when in the horizon and at ther mean distnueeThis is consi. derably less than the actual volue of the quantity, as determined by moderm ¥ciencenamely 57' 1": and it is practically, in the calculation of solar ,
