Mr W. Galbraith's Barometric Observations. 45 



16000 X 3 = 48000; which will afford some facility in recover- 

 ing them when indistinctly remembered *. 



We shall now proceed to the application of this formula. 



Example I. 



To determine the height of Allermuir, one of the Pentland 

 Hills, the following mean of a number of observations, with ex- 

 cellent barometers, were taken after the manner of those em- 

 ployed to obtain the height of Benlomond, given in a former 

 Number of this Journal. 



The observations were made on the Calton Hill, of known 

 height, S55 feet, with the Observatory barometer, by Mr Tho- 

 mas Henderson, and on the summit of Allermuir, by myself, 

 on the 26th of July 1828. 



Inches. 

 B = 29.549 T = 650.4 / = 57'.6 



b = 28.187 t' = 52 .4 t' = 52 .5 



B — 6 = 1.362 T — t'=13.0 110 .0 



B + 6 = 57.736 3 60 



- 39 6600 



Constant 48000 



Correct co-efficient 64600 



B — i reversed 2631 



64600 



16380 



3276 



109 



B + 6 67.736) 74365 ( 1288 



67736 — 39 



+355 



16629 



11647 1604 = H 



6082 

 4618 



464 

 462 



2 



• It may be observed, that the number 60 is ten times the number of 

 working days in a week, that the number 48000 is eight hundred times 60, 

 and — 3 is the twentieth part of 60, so that the whole of the co-efficients are 

 derived from one number (6), the number of work days in a week, and by 

 that means can hardly be forgotten. 



