﻿492 APPENDIX. 



<c and ascensional difference for Tirvalour, and af- 

 «.* terwards taking the differences algebraically, and re- 

 " ducing them to puis of a Gurry, as in the follow- 

 " ing table, the principles of the method will be 

 " evident. 



*' The fifth and sixth columns sufficiently explain 

 " the tables in page 253 and 254 of M, Gentil ; but 

 •' there remains a part more difficult, namely, why in 

 " calculating the Bauja" or the doubles of the firft 

 differences of the ascensional difference " .§-£■ of the 

 " length of the shadow is taken for the hist ; 4. of 

 " the first term for the second, and ~ of the first 

 " term for the third." " The primary reason of 

 " taking differences here, seems to be that the 

 " chords may be nearly equal to the arcs, and 



