APPENDIX, 

 high, the megameter affords a very accurate and expedi- 

 tious method of determining the height of all the points,- 

 when their diftances are found ; and thence, the heights 

 being known, of afcertaining immediately by a fingle ob- 

 fervation the fituation of the fhip, or the latitude of any 

 point by the bearings at the time of a meridian obferva- 

 tion: the diredion and rate of currents or tides may 

 alfo be found in this manner with great accuracy. I 

 made feveral obfervations during this voyage with the 

 megameter, fome of which I fiiall give as examples; 

 they were fuflficient to prove to mc the. great accuracy that: 

 may be attained with this inftrument after fome pradlice. 

 The utility of fuch a method, of obtaining a furvev on an. 

 enemy's or undefcribed coaft, as well as that of being able 

 to prove the truth of charts by a fingle obfervation, is 

 obvious.. 



June the fifteenth, the fliip being in latitude 60° 19',, 

 longitude 0° 39' W, Hangclifi" bore S 63° 00' W; 

 variation, 23° W. 



The altitude of the Carcafs's maft, by the megameter,. 

 was 35' 48"; height of the mad, 102,75 feet ;, hence. 

 the diftance between the Racehorfe and Carcafs was 

 9861 feet: angle between the Garcafs and IlangclifF,, 

 85' 48^;, between the. Racehorfe and Hangcliff, 87^ 00'; 

 From whence the difTerence of latitude was found 10' S;; 

 difference of longitude 17' VV. Therefore, the latitude 

 of HangcHff' is 60° 9'; longitude o^ 56' W. 



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