^2 GUILIELMI WENCKEBACH^ 



In triangulo ABC est 



' > V. Swina. Meetk, C. I. V. 15. 



l VBA = L BAC + ICS 



L YAB 4- L VBA = l aBC + L dAC + 2 Z, C 



= 2R + i C (v. >.%. B. L V. 15.) 

 sed Z YAB + l VBA = 5 + y + r + r' 



jgitur 5 + S' + »• + /' = 2R + i C 



r + r' = aR + Z,C — S — S' 

 et si suraitur r — r' 



r = iR + IC -irS + S') 

 unde L YAB = S -^ r = iR + §C + i(5 — S') 



et ^VBA = S' + f'^ iR + |C - i(S +S') 

 hinc Z BAC = 2R — Z YAB = iR — iC + |,S'— S) 

 sed Z B'AC = iR — i C 



ergo L BrtB' = i ( S' — S ) 



- itemque L B'BA = 2R - Z, VBA = xR — |C — | (S' — S). 

 In triangulo ABB' 



AB' : B'B = Sin. ABB' : Sin B'.\B (v. Sw. B. IX. v. 3.> 

 sive * j z— ^ Sin. ( iR _ j( C + S' — S ;) : Sui. | (S' — *> 

 i Cos. |, C -(- S' — S) 



z Cos |( C + 5' - S) 



cnde X = 



Sin. i(S' - S) 



Et si negligitur angulus iC propter ejus exigiiitatenfc 



z 0,0% |( 5' _ 5 ) 



X — 



Sin. i(S — 3) 



= z Cotg |(S' _ S) 



h. e. spatium horizontale inter duo loca aequale est difFerentiae conini altttudinum baro» 



metro invenicndae, multiplicatae pcr eotangintem dimidiae diQcreniiae angulorum cum 



zenith in utroque loco observatorum ( i ), 



3it, 



(l) Vid. FUI3IANT, Traiti ii Ctodisit, AH, 102, lofi »r JJftf 



