and Levelling, 6$c. 



Const log as before 

 t = 63.5 log x 2 

 <r =: 63.5 log 



F =°- 75 -r 



b — 29.725 log 



0.7435 log 



337 



7.57877 



9.97590 

 9.99042 



9.87128 



1.47312 



dh = + 1788.8 feet ... log +3.252552 



Collecting these numbers, and allowing 8.5 feet for half the 

 rise of spring tides, there will result 



Half the rise of tide, .... 8.5 feet. 



Height of station above high water, . 

 Height of Carnethy above station, 



Total height above mean level of sea, 

 Barometric height verified by levelling, 



72.1 

 1788.8 



1869.4 

 1880.7 



11.3 



Defect of trigonometrical height, 



Hence the probable error of this determination is about 11 

 feet too small. 



III. The height of the summit of Carnethy was determined 

 in a similar manner from Inchkeith. 



Mean zenith distance, . . . 88° 46' 51".5 

 B = 29.78 in. t — 60°, and r = 60° Fahrenheit. 

 A :? 74701.5 feet, bearing about S. 22° W. 

 Whence n — 0.08055, and dh == 1701.5 feet 



Here, however, the height of the station was got from Mr 

 Robert Stevenson some years ago, who stated the height of 

 the ground above high water by levelling to be 175 feet, 

 above which the axis of the circle was 4 feet. 



* This defect may in part be owing to the difficulty of determining the 

 first height accurately by the depression of the horizon of the sea, especially 

 in a narrow firth. 



