A VERY SENSIBLE HYGROMETER. 31 



accounts that Vv^e have, it appears very probable, that 

 this instrument has mc^re to do with the phenomena 

 ' of refractiofi, tlian either tlie barometer or thermometer. 

 If then we could obtain a number of observations of 

 apparent altitudes, together with data from which to 

 calculate the true, noting at the same time tl"ie hygi^o- 

 meter, barometer, and thermometer, perhaps some law 

 might be discovered, which might enable us to ascer- 

 tain the quantity of the effect of moisture on refrac- 

 tion. It was with this view the hygrometer above 

 described was constructed ; but not having yet had 

 an opportunity of obtaining the requisite observa- 

 tions, it is to be hoped, they may be made, b}'^ those 

 who are in possession of time and instruments, equal 

 to the ucdertaking. 



