53 



As the sum of the readings of the barometer or Ane- 

 roid is to their difference , so is 55 '000 (or twice the 

 height of the atmosphere in feet) to the elevation 

 required. 



To find the height of Fairlight Down near Hastings, 



in. in. 



Let the reading of the Aneroid on the \ _ o n . ft c 



Marine Parade, Hastings f " 



at the bottom ofl 



the windmill on the Down / 



= 29'44 



Sum... =59-49 



30-05 

 29-44 



0-61 = difference. 



in. in. feet. feet. 



.-. 59-49 : 0-61 : : 55-000 : 564 nearly. 



The table of elevations computed by the above formula 

 at the temperature of 55, and the lower barometer at 

 30 inches, may be found interesting to those who may 

 wish to see at a glance the heights corresponding to the 

 depressions of the barometer. 



Thus on the Grampian Hills a depression of 4 inches 

 gives an elevation of 4000 feet ; at the crater of Mount 

 Etna a depression of 10 inches gives 11,000 feet; and 

 on the summit of the mountains of Thibet, supposed 

 the loftiest in the world, a depression of 20 inches gives 

 an elevation of 27,500. 



THE END. 



Printed by Richard and John K. Taylor, Red Lion Court, Fleet Street. 



