tity dt wn 

 temperatu 



by stronger eradication' of heat, l)e 



rain wo 



nia tall. Dewfiw 

 oled below Aetei 



rmsonlyoE 



ingair. This difference may amo 



unt to fi 



■om 7 to 25 degre 



es Fahrenh 



The same quantity of vapor 



contain* 



•d in a certain vol 



nine of air 



ferent pressure upon the inclosing 

 or elastie force, can be measured 1 



vessel, l 



irometric column, 





aque!m^ 



essurec 



£ the air itself, p* 



clastic force of VI 



irtly to the 

 ipor in the 



of the atmosphere also varies durii 



ag the d 



ay with the chanjj 



;ing temper; 



tity of weight of vapor in the air. 









As the hygrometrical conditio 



ms and 



laws of the atmo 



sphere are 



known, it is presumed that the rei 



narkabh 



3 results obtained 



by this ex 



acceptable to the friends of mete. 



-rology. 



They throw soi 



ue light oi 



conditions of a district which in tl 



lis, as in 



. most other respe 



cts, differs 



Eastern States of the Union. F 



rom oui 



r observations wi 



- cannot d 



laws, because the observations coi 







ong period: 



but have mostly been taken tor short times only, at numerous diiterent points; mil 

 further explorations may complete the results. The observations have been executed 

 with as much care as was possible under the circumstances, and the unitornnty oi the 

 results, of which the following- tables and diagrams afford a proot. append highly satis- 

 factory and testifies to their relative correctness. Still I do not hesitate to declare t u.t 

 the obstacles in the way of obtaining absolutely correct results, very great at nxed 

 observatories, as those best know who have studied mo>r fully these ^^''^ 

 scarcely be obviated in the field, where the most simple arrangements can on 5 

 used to advantage. 



The observations were taken with an August's hygrometer. 1 he dry and wet 

 bulb thermometers were suspended in the shade of the instrument wagon, genera y > 

 or 7 feet from the ground. I missed very much a suitable casing which would nave 

 better secured the observations against vitiating outside influences. The indicate .11s , ,t 

 a Mason's hvjrrometer in which a wide glass tube, closed on top, and fastened between 

 the two thermometers, contained the water for moistening the wet bulb, were found to 

 24 B U 



