Cmfideral'ions on Dr, Mutton's Theory of Rain. 6t 



caloric, and that one part of caloric will raife its temperature 

 one degree in any part of the fcale 5 if we wiOi to convert this 

 into a unit of moiji air at the fame temperature, it will not be 

 fufficient merely to add the proportion of water, fuppofeOjOOi ; 

 for this water, being itfelf a /iquid bafe, will require nearly as 

 much additional caloric to conftitute it gas, as the portion of 

 air which was necelTiirily excluded from the unit took away 

 with it. When we have added this proportion of caloric 

 (which would have raifcd the dry air many degrees in tem- 

 perature) together with the water, we fliall have a unit of fa- 

 turated air. 



Further, if we would raife the temperature of the latter 

 10, 20, or 200 degrees, and ftill preferve the faturation, we 

 fliall find it iifipoflible to proceed without an expenfe of power 

 adequate to the rate of folution, befides that proportion which 

 is employed in raifing the temperature through thofe fuccff- 

 five intervals of the fcale which are taken as Ihe Handard of 

 folution. 



Now, in the cafe of equably advancing folution, if, as often 

 as the thermometer has rilen lO', a quantity of caloric ecpial 

 to 100'' has been imperceptibly fupplied in addition, this is 

 of no importance in the iflue, lince the temperature is (lill a 

 true fropurltonatc meafure of the power of folution in the ex- 

 Irtmes and in the mean : but in thofe of accelerated and re- 

 tarded folution it is otherwife; for here the very terms of the 

 propofition require that, as we advance in the fcale, each de- 

 gree of temperature may anfwer to 10, 12, }6, ^4, of folution, 

 or inverfely, and confequenily to fimilar proportions oi added ^ 

 poivcr. Now if in each unit fucccllively faturatec] atdillerent 

 degrees there enters the due proportion of power which it 

 needs mull, then in every mixture that can be made of them 

 the total power of folution i\s well as the whole quantity of 

 water will be prefent, and there will be neither fuper- nor 

 under-laturation let the temperature rel'ulting from the mix- 

 ture be what it may *. 



Admitting, therefore, that caloric, or the caufc of tempera' 

 ture, is alfo a neceflarv conftituent part of aqueous vapour in 

 wliatfoevcr way it be formed, and that the doctrine of capa- 

 cities is well founded, we mull rcjcd the theory of Dr. iiut- 

 ton altogether. 



P. S, Whether the phrafe of " the diffolving power of air 

 on water" was connected in the mind of Dr. liutton with 



■" The rem iiidcr of the jiapcr, as rt:id btfon- the fbciety, is fiipprencd 

 by dc(irc of the autlior, who has corTHiiuiiuatcd what follows ill it;, (dace, 

 aud in wliicli hii ;ti)i;ni for thii will ,ipj>cui. — EtiHUK. 



the. 



