

upon the Antique Dials. 



89 



IX. 



VV r e have hitherto considered only the general equation, without any re- 

 ference to the numerical values of n. These, for the several hour-lines, are 

 as below : 



x. 



We have seen, that whatever be the value of n, the hectemoria pass 

 through the intersections of the meridian and equator. When, however, the 

 great circle chords of the hectemoria are substituted for them, these chords 

 belonging to hectemorial arcs whose extremities have all the same declina- 

 tion (the tropics, for instance), these chords do not all tend to the same point 

 on the sphere. Neither do the tangents to the hectemoria, at their inter- 

 section with the equator, tend to the same point. 



The second is a case of the first ; viz. when the declination of the paral- 

 lel through which the chords of the hectemoria pass is ; yet the simpler 

 method of finding the co-ordinates in that case, is to discuss it independently 

 of the general property. 



