Mr Galbrailh's Barometric Measurements of Heights. 323 



top of Camethy, and the Caltonhill of known height, 355_feet above the mean 

 tide at Leith, and the upper barometer 3.5 feet under the summit ? 

 By formula (12), 



B = 29.339, 

 b = 27.745, 



: 66.2, 

 : 55 1, 



t = 63.7 

 / = 55.4 



B_6= 1.594,' 



11.1 t + t' = U9.l . 



2.8 



B + 6 = 57.084 



119.1 



119.1 

 6 



7146 

 48404. 



0.4 == 



888 2.4 300 



222 — 



2.8 



correction = — 31.08 B — b = 55550 reversed 



495.1 



55550 



27775 



5000 



222 



B + i 



J.594 

 57-084 

 0.03 X 0.03 



. 57.084)88547( 1551.2 

 • • • • 57084 + 355.0 



+ 3.5 



31463— 31.1 

 28542 + 0.5 



Now, 



= 0.03 nearly, and 



= 0.0003, therefore 

 0.0003 X 1551 = 0.5 foot nearly 



2921 

 2854 



67 

 57 



1879.1 



10 



The true height is therefore 18/9 feet. 



So that the terms of the series formerly alluded to are in this case unne- 

 cessary, and the effects of latitude and height would be nearly insensible. 

 The calculation becomes Ln consequence remarkably simple. 



The following are the heights of the same points, by a concise set of tables 

 accompanying this paper, which to those not fond of formulae, and the arith- 

 raetical operations thence required, will be useful : — 



B = 30.164, 

 b = 19.530, 



80°, t = 80' 

 .55, t' = 5b 



r — t' =,25 , t + t' =\35 

 30.100 gives, in Table I. 

 60 proportional parts, 

 4 .... . 



30.164 gives . 

 b = 19.500 gives 8993 feet 

 30 p. pts. 40 



19.530 gives 9033 

 .r' = 25" Table II. 4- 67.1 



Sum, 9100.1 

 Approximate height or difference, 



20335 feet. 

 52 

 3.4 



20390.4 



9100.1 



(Carried forward,) 1 1 290.3 



