during an Atrial Voyage. 



117 



Remarks by Mr. Daniell. 



It is much to be regretted that Mr. Green omitted to take 

 the point of deposition before he commenced his ascent, or 

 after he had again landed, as such an observation would have 

 added greatly to the value of his experiments; as they stand, 

 they will, however, form a valuable addition to any future ob- 

 servations which it is to be hoped that he may be induced to 

 make. Some interesting particulars may even now be derived 

 from them. I have subjoined a calculation of the different 

 heights as observed by the barometer, and the density of the 

 vapour at those heights, as indicated by the hygrometer. The 

 different degrees of dryness are also added in the following 

 table. 



The state of the atmosphere on the day of Mr. Green's as- 

 cent was evidently not favourable for ascertaining the grand ques- 

 tion of the rate of decrease in the density of the aqueous va- 

 pour, when the atmosphere is undisturbed. By au experiment 

 which I made myself in the country not very distant from the 

 point at which he descended, the degree of precipitation on tbp 

 earth's surface, at two o'clock, was 64°, exactly the same as 

 he found it at the height of 9,893 feet ; so that it is very pro- 

 bable that there was but little differeiipe in tlie density of the 

 vapour in that immense stratum. The very small decrease in 



