312 On the Theory of Mixed Gases, 



heated to 59 degrees in a dry tube ; let this 

 number be / ; then g- — /= 33.50 : but/, or the 

 Jipring of vapour at 59 degrees, is .507, accor4* 

 ing to Mr. Dalton; theny^' = 551, 164; hence 

 c =16,15 inches ; which expresses the height 

 of the barometer, together with the .column of 

 mercury, contained in the tube. If the tem- 

 perature be stated at 95 degrees, c will amount 

 to little more than 8 inches : now it is highly 

 huprobable that Mr. Schmidt made his ex- 

 periments when the barometer " stood at a 

 height indicated by either of these numbers.— 

 This application of the theory to practice,, 

 affords a presumptive evidence, jth^t the prin- 

 ciples of it are not altogether just, supposing 

 the experiments of Mr. Dalton ; and Mr. 

 Schmidt to be correct : but a positive proof of 

 a want of accuracy; in these principles may be. 

 obtained by introducing a small change into 

 th:^ manner of conducting the experiment 

 made with moist air. This alteration consists 

 in discarding the stopple of mercury^ and subn 

 stituting the simple pressure of the atmosphere 

 in the room of it : because when this sub- 

 stance which is impenetrable to steam, has 

 been removed, the redundant vapour will, ac- 

 cording to the theory, flow into the . atmo- 

 sphere, thereby leaving the moist air of the tube 

 to follow the law of expansion observed by 



