STATE OF 



VAPOUR 



ds from to 100 yardi 



100- 



200 



200- 



300 



300- 



400 



400- 



500 



500- 



600 



600- 



700 



700- 



800 



800- 



900 



900- 



1000 



1000- 



1050 



above 



105t) 



IN THE ATMOSPHERE. 119 



I above Derwent Lake, 1 times, 



42 



62 



179 



374 



- - 486 



416 



367 



410 



518 



419 



- 2098 



Total 5381 

 His obfervatlons could not be particular above 1 050 yards. No maximum 

 that being the perpendicular height of Skiddaw. There is not ]IimeTa"by that 

 therefore any maximum of height fo much as hinted at ; and author's obfer- 

 the minimum is 0, or when the clouds reft on the ground, an ^^^'°"** 

 event occurring in every part of Great Britain two or three 

 times a year. Were we to form a conjecture from the above 

 obfervations relative to the greateft height at which clouds are 

 formed in this country inordinary. It would be about 1 mile; 

 but in fummer they are probably foraetimes if mile above 

 the level of the fea. 



Confidering the great fervice that Dr. KIrwan has rendered Obfervations, or 

 to meteorology and chemiftry, and my own obligations to him ^f p^^ Kh-wan's 

 on thofe accounts, it is unpleafant for me to fignify diflentfrom and Mr. Dalton's 

 the doarlne he inculcates refpeding the ftate of vapour in the ftate'jjafmjf- 

 atmofphere. At the fame time that his Interefting feries of pheric vapour, 

 eflays in the eighth volume of the Tranfadtlons of the Royal 

 Irilh Academy were in the prefs, my eflays on the force of va- 

 pour from water and other liquids, both in a vacuum and In 

 air, and on evaporation, publiflied In the Manchefter Tranf- 

 a6lIons, Vol, V. Part 2, were alfo In the prefs. He holds the 

 notion of a chemical folutlon of water In air ; and I maintain 

 that vapour fubfifts in air as it does In vacuo, conftltuting a pe- 

 culiar atmofphere, mixing but not combining with any of the 

 gafes of the compound atmofphere. On my principle the den- 

 lity of the aqueous atmofphere at any height is totally Inde- 

 pendent of the denfity of the compound mafs of air, and Is 

 to be afcertalned by knowing the denfity of vapour at the 



earth's 



