304 MEMOIR RELATIVE TO 



trigooometrical dedaftions from fixed points. I have ufed the fanie 

 peak Ndo XII and XIII both at Casipiir and Ajzdgcrh. 



• CASES 3 and 4. 



I HAVE already noticed that to 2Xi2im grent accuracy by thefe methods, 

 the difFerence of heighth of the flations fiiould be confiderablej and 

 the diOance not very great ; efpecially when the angle of elevation or 

 depreffion, can be obTerved at one ftation only. N6t being provided 

 with barometers, I have no fuch example to offer, as I could wifh, or as 

 the methods themfeives are fully fufficient to afford* 



When the arch of dilUnce is very great, and the angle of elevation 

 extremely fmall. the varieties to which the ref radive fiate of the atmof- 

 phere is fubjed:, v#ill alone occafion difcrepancies of vafi; amount. 

 That this is the cafe, will be clearly feen by the following approxima- 

 tions, m which I have fuppofed the flations to be precifely on the fame 

 level with Cdsipur, which is not of courfe, flriflly true. 



STATION JFZELGERH, EXAMPLE I. 



l< eJraciiO'l. 



Oistimce No. Xll. by c«se Sd,,, 

 i'ru« Distancfl of No, XH...,,, 



Krrorg. ,, „ , 



778*^0 



78843 



-lO^S 







Befraci 



ion 







DistniiCf N 

 True Dista' 



0. xni. 



ice No. 



by c«s« 



XHJ.. 



3<i 



«- 9 e » 



Errors... 







-»•••• 



« « 





■ 









i 



' 











79779 

 80895 



-! ! 16 



Refraction, 



)istance No. X V. bv cnse 3d. ..,, . 

 Tiue Distance No. XV.,.,,..,,.., 



'jrrbrs, 



87107 

 8fi018 



F 



1 '2 



WIGS 



7884 3 



+ U23 





T 



■12 



82315 



8089 S 



4-14^3 



1 



T2 



90358 



89018 



4-1540 " 



79424 



78843 



+ 581 



81403 

 80895 



89371 

 89018 



4-353 



•2T 



79018 



78843 



4-175 



80895 



4-31 



88812 

 89018 



-^06' 



s . 



