BAROMETRICAL MEASUREMENT OF HEIGHTS LOOMIS. 



391 



PART II. 



Correction due to T — T', or the Difference of the Temperatures of the Barometers at the two Stations. 



TViis Correction is Negative when the Temperature at the Upper Station is lowest, and vice vers i. 



Correc- 

 tion. 



154.5 

 156.8 

 159.2 

 161.5 

 163.9 

 166.2 

 168.6 

 170.9 

 173.3 

 175.6 

 177.9 

 180.3 

 182.6 



App. 



Alt. 



Foet. 



1000 



2000 



3000 



4000 



5000 



6000 



7000 



8000 



9000 



10000 



11000 



12000 



l.SOOO 



14000 



15000 



16000 



17000 



18000 



19000 



20000 



21000 



22000 



23000 



24000 



25000 



PART III. 



Correction due to the Change of Grav- 

 ity from the Latitude of 46° to the 

 Latitude of tlie Place of Observation. 



Positive from Lat. Oo to 450 ; 



Negative from Lat. 45° to 90°. 



Latitude. 



450 



Feet. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



D 



PART 

 IV. 



Correction 



for 

 Decrease 

 of Gravity 



on a 

 Vertical. 



Always 

 Positive. 



Feet. 



2.5 



5.2 



7.9 

 10.8 

 13.7 

 16.7 

 19.9 

 23.1 

 26.4 

 29.8 

 33.3 

 36.9 

 40.6 

 44.4 

 48.3 

 52.3 

 56.4 

 60.5 

 64.8 

 69.2 

 73.6 

 78.2 

 82.9 

 87.6 

 92.5 



51 



PART V. 



Correction due to the Height of the Lower 

 Station. 



Always Positive. 



Height of Barometer at Lower Station. 



Feet. 

 0.2 

 0.3 

 0.5 

 0.7 

 0.8 

 1.0 

 1.2 

 1.3 

 1.5 

 1.7 

 1.8 

 2.0 

 2.2 

 2.3 

 2.5 

 2.7 

 2.8 

 3.0 

 3.2 

 3.3 

 3.5 

 3.7 

 3.8 

 4.0 

 4.1 



App- 



Alt. 



Feet. 



1000 



2000 



3000 



4000 



5000 



6000 



7OO0J 



8000 



9000 



10000 



11000 



12000 



13000 



14000 



1,5000 



16000 



17000 



18000 



19000 



20000 



21000 



22000 



23000 



240001 



250001 



