APPENDIX. 



149 



Means ufed to afcertain the Height of the Mountain 



Geometrically. 



A point was fixed upon, in the moft convenient place 

 the ground would admit of between the fummit of the 

 mountain (a well-defined objedl) and the fea fide ; from 

 hence, in a right line from the mountain, a ftaff was placed 

 at the fea fide, by a Theodolite made by Ramfden, with 

 two telefcopes and double Vernier divifions. The inftru- 

 ment was carefully adjufted ; firft, by levelling the ftand 

 with a circular level, and afterwards the whole inftrument 

 by the crofs levels. From hence (A) at right angles to 

 the ftation at the fea fide (C) and the top of the mountain 

 (E), a bafe was meafured each way to (B) and (D) of 

 eight lines of feventeen fathom each ; in all, five hundred 

 and forty-four yards. The divifions of both the Verniers 

 were carefully examined, both at fetting ofFthe ftation by 

 the fea fide, and thofe at the extremities of each bafe, 

 the fixed telefcope being kept diredled to the fummit of 

 the mountain, and the moveable one direded at right 

 angles each way, both divifions of the Vernier coinciding 

 exadly. Station ftaves were fixed perpendicular by the 

 vertical hair of the telefcope. The altitude of the mountain 

 was then taken witli the vertical arch, as a means of de- 

 tedling any error in the obfervation, and was found to be 



Z - 8° 50'. 



