510 M. Neumayer on Aqueous Vapour 



described these compounds as consisting of carbonic oxide in 

 union with the alcohol-radicals. In the reaction which forms 

 the subject of this paper, carbonic oxide is seen to unite with the 

 alcohol -radicals and to form a genuine ketone : a more remark- 

 able confirmation of the theory is hardly conceivable. 



LXXIII. On Aqueous Vapour and Terrestrial Radiation. 



By M. G. Neumayer. 

 To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



I TRANSMIT to you a communication from M. Neumayer, 

 which I trust will have the effect of stimulating other me- 

 teorologists to enter upon and pursue the line of inquiry which 

 he has so ably and zealously begun. There is, in my estimation, 

 no result of physical science more certain than that the aqueous 

 vapour of our air exerts a powerful influence upon the radiation 

 from our earth ; and there is none, I imagine, more likely to 

 guide the really scientific meteorologist to results of permanent 

 value. John Tyndall. 



To Professor Tyndall, F.R.S., %c. 



Frankenthal, Pfalz a. Rhein, 

 My dear Sir, May 4, 1866. 



You will perhaps remember that some two years ago I sent 

 you some original observations made at the Flagstaff Obser- 

 vatory, Melbourne, bearing on the absorption of heat by aqueous 

 vapour, and its relation to terrestrial radiation. At the time 

 when I did myself the pleasure to call upon you at London, you 

 stated that great pressure of other matters did not admit of 

 your undertaking the task of discussing those observations ; and 

 in consequence of this I had the extensive labour of classifying 

 and condensing so large a number of figures done in my bureau 

 of computation, established with the object of publishing discus- 

 sions on the magnetic and meteorological observations made by 

 me during the years 1858-63. In the annexed Tables, four in 

 number, you receive the results of my labours in this direction, 

 which I feel great pleasure in putting before you. 



In order that you may be able to form an opinion as to the 

 manner in which the observations were made, I subjoin the fol- 

 lowing remarks. 



(1 ) The observations were made at all times of the day and 

 the night whenever the sky was clear, i. e. the zenith perfectly 

 free from clouds. 



(2) The tension of aqueous vapour and the degree of relative 

 humidity were observed by August's psychrometer, continually 

 checked, however, by Dobereiner-Regnault's aspirator hygro- 



