84 Mr Nixon on the [Feb. 



Article III. 



On the Measurement of Heights hy One Barometer, with the 

 requisite Tables. By Mr. J. Nixon. 



{Concluded from p. 42.) 



Use of the Tables. 



Table I. — Having given the follovring observations, to prepare 

 them for the calculation of the altitude. 



Station. Time. Pressure. Mercury. Air. 



(No. 1.) Gearstones Inn 9^ 15'" . . 29-022 . . (46°) 



Cam Fell 13 20 28-188 .. (43) .. 42° 



Gearstones Inn 16 15 29-128 .. (45) 



Temperature of the air at Gearstones at 13'' 20*" = 45°. 



Reduction of the Pressures at Gearstones to one Temperature, and 

 Interpolation to 13'' 20"". 



Pressure at 16" 15-" .... 29-128 (45°) 



Add for 1° of difference oftheinterior 



tlierms. = (46°) - (45°) -003 {See Table 1.) 



Pressure at 16" 15'" .... 29-131 (46°) 



Ditto 9 15 .... 29-022 (46) 



Interval 7 = i ) -109 



-015-6 rise per hour. 



Pressure at 9-15 29-022 



Rise in 4-5 -064 



Pressure at 13-20 = 29-086(46°) 



The scale being so fixed as to render the corrections for capa- 

 city and capillarity superfluous, the observations prepared for 

 calculation will be, 



Gearstones Inn 29-086 (46) 45 



Cam Fell 28-188 (43) 42 



In the following set of observations, the neutral point of the 



barometer was 30 inches ; the capacity ^ ; capillarity -100 



inch. Hence the pressures must be diminished by the constant 



quantity -522 inch. 



■■:p:-^.i^ii. - Calculation. 



,' ■>'i ■ ■ 



Capacity plus 1 = ^ )30'000 neutral point. 



•652 

 Capillarity — -100 



Constant reduction . . '552 



