PHYSICAL AND LITERARY. 141 



logs, of the aphelion and perihelion diftances, 

 the remainder will be the log. tang, of an 

 angle ; to this angle add half the anomaly of 

 the excentric j let the fum be called the 

 angle C ; to the log. tang, of the angle C, 

 add half the fum of the logs, of the aphelion 

 and perihelion diftances ; from this fum, fub- 

 trad the log. of the mean diftance ; the re- 

 mainder will be the log. tang, of the coequate 

 or true anomaly. 



Let CL be the lelTer axis of the planet's 

 orbit. "Becaufe, from the nature of the 

 ellipfe, the fquare of CL is equal to the re- 

 dlangle ASP, the log. of CL will be equal bQ 

 half the fum of the logs, of AS, SP : and, be- 

 Caufe the tangent of the angle KSH is to the 

 tangent of the angle GSH as HK to HG j 

 that is, from the nature of the ellipfe, as LC 

 to CA ; therefore, if to the log. tang, of 

 the angle GSH, the log. of CL be added, 

 and from the fum the log. of AC be fub- 

 tradled, the remainder will be the log. tang, 

 of the angle KSH. 



Again, the fine of the true anomaly is to 

 the fine of the anomaly of the excentric, as 

 the leffer axis of the orbit to the diftance of 

 the planet from the fun. 



Because 



