A- SURVEYOF KEMAON, 295- 



(Rxperience in mearurements of this defcription, arc well aware^ that 

 five miles in an hundred is not an impofTible error. 



The known poll tions of fnowy peaks aSbrd a ready mode for detef'^ 

 mining the true geographical place of any ilationj .from, .whence the^r 

 are vifible, and;rnay. thsrefor^ be applied to , the eorre6tion of maps 

 rompiled from, route, fiirvieys of the defcription juft named. ^ It may" 

 be well to detail the feveral cafcs, in v/hich they rnay be fo applied, and 

 I. h^ve appended to this memoir examples of mod of them, from which 

 a tolerably correcl idea may be formed, of the degree of iccuracyj 

 which may be expelled to attend the refulrs, 



CASE 1st, ■ 



Thrbb fnowy peaks, the geographical po-fitions of which: are knowHj 

 beiag vifibb from ajjy pUce or flation— and the horizontal angles they 

 fubtend at that flation being obferved— the diftance of the'^{la^i'on from 

 e^ch peak, together with its .latitude and longitude, become known alfo* 



CASE 2d..>_/. 



The latitude. of a; (lation being obferved, aid alfo the true azimuth 

 of a fingle known peak.— -the diflance between the peak and the ftatioDj 

 a^d the longitude of .the latter, become known alfo, 



Thw angle of elevation of any peak, the heighth and. portion of which 

 are known,. being obferved, and the heighth of the flation b-ing alfo 

 known — thefe data a^e competent t-) give the diftance between the 

 peak and the llation :.-and if tlie-azimuth of tiie peak be obferved, the 

 latitude and .longitude or the place pf. obfervation becqme known alfo. 

 This cafe compnfes the met ifdjidverted Lo by M. Humboldt in hi's 

 " Georraphicil EnT.iy,". unl^tr ihv de-nomination of " V. rtical Bafes," 

 and which he aprcirs to have adopted, very extcnfively. The fur- 

 T^y ofa mcu.itain province may thus be accomphdied by aid of b.^^ 



