52 



The height of the Atmosphere being assumed at 27'500 

 feet) with the Barometer at 30'00 inches and the 

 Thermometer at 55 of Fahrenheit, the following Table 

 of Elevations has been computed, answering to the 

 corresponding depressions of the mercury in the Ba- 

 rometer. 



The following rule, which gives results very near 

 the truth, will be useful in deducing elevations from the 

 Aneroid. 



