IS^ ExhalatioJi of Bicarbonate of Ammonia by the Lungs. 



empty space in the ball (not occupied by water), after adding 

 for the increase of its elasticity by the increase of temperature, 

 it was yet to be augmented by the elasticity which steam alone 

 of the same temperature would possess, to give the elasticity 

 of the mixture. 



Let i = bulk of air introduced into the ball, measured be- 

 fore its introduction. 

 A = its elasticity (expressed in inches of mercury, or the 



height of the common barometer). 

 B=bulk occupied by it jointly with the steam in the 

 ball, when their common temperature, governed 

 by that of the water in the pan, is t. 

 1 : r= ratio of elasticity which the air had before introduc- 

 tion to what it would have by augmenting its tem- 

 perature to t; or, which is nearly the same, the 

 ratio of expansion of air by the augment of tem- 

 perature to /, when under the same pressure. 

 E = pillar of mercury (in inches) which steam of the 

 temperature t would support: 



2bK 

 Then E + - ^ =pillar of mercury (in inches) which would be 



supported by the elasticity of the mixture at the 



temperature t. 

 Example. Suppose Z» = | cubic inch; A = 30 inches; ^=102° 

 10 to 11, ratio of elasticity of air at the temperature at which 

 it was introduced to what it would possess at 102, consequently 

 2=1-1; B = 6 inches, and E (by the table) 1*95. Then 

 1*95 + 2 X 30 X ri-^6 = 4.'70 for elasticity of the mixture, or 

 column of mercury it would support. 



XXV. On the Exhalation of Bicarbonate of Ammonia by the 

 Lungs. By Lewis Thompson, M.E.C.S., S^c. 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 



HAVING lately had occasion to ascertain the amount of 

 moisture given off by the lungs of several healthy indi- 

 viduals during a fixed period, I was induced to examine the 

 nature of the fluid thus condensed. The result has proved 

 that bicarbonate of ammonia is constantly exhaled from the 

 lungs to the extent of rather more than three grains every 

 twenty-four hours for each individual; and although this 

 quantity may appear trifling, yet the amount arising from a 

 large population like that of London is well worthy of notice, 



