1823.] Mr. Moyle on the Height of the Barometer. 377 



There are different ways to calculate the correction from this 

 table ; the first, and most accurate, is, that of multiplying the 

 sum in the table corresponding with the observed temperature 

 by 30, which gives the expansion for 30 inches of mercury. 

 Then let the observed height of barometer be 28*420, attached 

 thermometer 72°, and we shall have 4348 x 30 = 13044. 

 Then 30-13044 : 30 : : 28-420 = 28-29697. 



The second, the one I always adopt, as being more expedi- 

 tious, is by multiplying the sum corresponding with the temper^ 

 ature by the observed height of mercury, and then taking it from 

 the observed height, viz. 4348 x 28-42 = 1-2357 - 28-420 = 

 28-29643, differing a mere nothing from the first method.* 



It appears from the Ann. de Chim. et Phys. that the meteo* 

 rological table published monthly in them has the proper correc- 



* The correction obtained by this method must be added to o» subtracted from the 

 observed heights, according as the temperature is below or above the standard tempera- 

 ture, or 32° of Fahr. 



