72 



not supersede the use of methods in which shorter tables ar6 

 employed, although these methods should be somewhat 

 longer in practice, provided they be equally plain. To 

 many persons the necessary expence of the volume will be 

 an objection, many will consider its bulk inconvenient, and 

 many disliking such extensive tables with double arguments, 

 will even prefer the former method wliich those tables v^ere 

 intended to facilitate. 



The method pointed out in this paper is closely connected 

 with Mr. Dunthorne's own method, and still more closely 

 with that method improved by Dr. Mackay. It has no 

 distinction of cases, requires only short tables with single 

 arguments, no proportional parts except what can be taken 

 out by inspection, and these for only one quantity besides 

 the conclusion. If it be thought somewhat longer in practice 

 than that by the extensive tables of Mr. Mendoza, it is not 

 less plain, and, by the assistance of a table particularly ar- 

 ranged, may perhaps be as quickly computed. 



As examples are given, it will be easy for those conversant 

 with the practical part of the subject, to form an accurate 

 opinion concerning the method here proposed. 



Besides investigations immediately connected with this 

 method, an investigation is also given of a formula for the 

 correction of the distance. 



Let H = apparent altitude of the sun or star. 

 H' = apparent altitude of the moon. 

 h = true altitude of the sun or star. 

 h' = true altitude of the moon. 



D 



