of Eclipses, and Especiallg of Law Eclipses 15B 20. The latitude is the base (Chujo) : the square root of the sum of their squares is the hypothenuke (rata) : subtract this rom half the sum of the nmeasures and the remainder is the amount of obscuration (guisa) at the given timo. 21. If that time be after the middle of the eclipse, subtract the interval from the half-duration on the side of separation, and. treat the remainder as before : the result is the amount remaining obscured on the side of soparation. The object of the procosy taught in this pasRnge is to determine the amount of obscuration of the ecligsed body of any given motnent during the continuKnee cf the eclipseIt, as well as that proscribed in the following pusage, is a variation of that which forms the subject of verses 12 and 13 above, being foutded, like the latter, upon a consideration of the right-angled triangle formed by the line joining the sentes of the eclipsed and eclipsing bodies as hypothenums, the difference of blheiz longi. tudes aus perpendicular, and the Inoon's latitude ५se. And whorea8, in the toximez problemwe had the base and bypotheruse given to find the ५%rpendiculur, here we have the base and perpendicular given to find the hypothenuse. The perpendicula is furnished us in tiaeand the rule supposes it to be stated in the form of the interval between the given moment and that of contact or of separation: a form to which, of course it may readily be reducod fron any other mode of statement. The interval of time is reduced to its equivalonh as difference of longitude by a propor tion the reverse of tibit given in verse 1B, by which difference of longitude as converted into time; he man's la ( {lon calculat:}; to h। two whe hypothenuse is educed; and the comparison of bix with the sm of the radii gives the measure of the annount of theuration Ver४७ 21 stems altogetheuprium i me!ely strate the method of proceeding in euse the time given falls anywhere between the middle al he tend of {h¢ ¥clipse, as it the specifications of the py::din, versex appli only to 1 ime becurring before the middle lerus he tze general it their character, and include the former &use no less than the latte}. When he t!clip8c is one of the sun allowance needs to be unadu for the vagintion of payollax during it continuance; this is to y the peoce3x described in verse 19, of which the explanation will be given in the notes to the next chapter (v. 14-17). In verse 20, for the first and only fine, we have latitude called instead of ऊikshedus elsewhere. In the sumr v®se, the term employed for hypothenus is hearing, organ of Hearing this, as well as the kindred , which is also once, or twice employed, is a synonym
