Description of the Mountain Barometer. 57 



to acquire the temperature of the air, and then to make this 

 correction according to the rule given above, from the dif- 

 ference of the two detached ther77iomctcrs ; and this baro- 

 meter, from the lightness of its mounting, will have the 

 advantage of taking the temperature oF the air sooner than 

 those formerly made with solid wooden cases. 



It may not be improper to give an example of the method 

 already detailed. 



Observation at bottom 29*400 Therm, in air 45 

 . at top - 25.200 Therm, in air 41 



2 I 54-600 2 I SQ 



Mea^ - 27*300 Mean heat - 43 



Standard - 32 



Difference - 42 tenths — 



Value of a tenth by the table 95*5 feet. Difference J 1 



1910 

 3820 



Approximate height - 4011-0 feet 

 Do. by sir G. Shuckburgh 401 6-0 



Error - 5 feet 



Correction for Temperature. 



For 8° = 2 hundredths - - 80 feet 

 For 3** = 3 four hundredths - 30 



Correction -f 110 

 Ditto by sir G. Shuckburgh - 107*4 ^ 



Error -j- 2-6 



Approximate height by me 4011 By Sir G. $. 4016 

 Correction for temperature 110 107*4 



Result - 4121 4123-4 



Example 



