56 Mr. DanieWs Reply to %. [Jan. 



Article IV. 



A Reply to some Observations in the Revieiv of An Essay upon 

 the Constitution of the Atmosphere. By J. F. Daniell, FRS. 



(To the Editor of the Annals of Philosophy.) 



MY DEAR SIR, Goxecr.street, Dec. 10, 1823. 



In the review of my Essay upon the Constitution of the 

 Atmosphere contained in the last number of the Annals, your 

 correspondent Z appears to me to have fallen into some miscon- 

 ceptions which I should be sorry to leave uncorrected in a work 

 of so much authority. I therefore trust that you will do me the 

 favour to spare me room for a short reply. 



In the first place, it is objected to my theory, that " it 

 rests upon the sandy foundation of assumed partial changes of 

 temperature in the higher regions of the atmosphere, of the ex- 

 istence of which we have very insufficient evidence." This 

 assertion, I must own, greatly astonishes me : for I certainly 

 conceived that no meteorological fact rested upon better autho- 

 rity. I thought it indeed to be so generally admitted, that I did 

 not refer in my Essay to the particular observations upon which 

 it is founded, but merely illustrated it by the observation of 

 De Luc, of the sudden rise of temperature accompanying the 

 formation of cloud at a great elevation. I might now appeal, I 

 believe, to every ascent of every mountain, and every aerostatic 

 voyage, during which the thermometer has been consulted ; for 

 they all appear to me to agree in the same result. Among the 

 latter, more particularly, there are abundant instances in which, 

 not only the temperature of the atmosphere has not followed 

 the regular progression due to the density, but warm strata have 

 been found interposed between cold, and cold between warm. 

 I shall content myself, however, at present, with referring Z to 

 the simultaneous registers kept at the summit of St. Bernard 

 and at Geneva, and which are published every month in the 

 Bibliotheque Universelle. He will there find that the difference 

 of temperature between the two stations is perpetually varying, 

 and that, although the changes oscillate round the point of equi- 

 librium, the general law of the decrease for the altitude is only 

 developed from a mean of many observations. 



The second objection is, " that to evolve so much heat as 

 would raise the temperature of a considerable mass of air, and 

 cause it to diffuse itself rapidly into distant regions, would 

 require the condensation of a greater quantity of aqueous vapour 

 than is likely to be present in any given space, and also that 

 this condensation should not be gradual, but should take place 



