300 



HYGROLOGY, AND ITS CONNICTION WITH METEOROLOGY. 



ties of evaporated luater that can subsist in one cubic foot of air 

 with these three degrees of heat ; but by the rate of its pro- 

 gress, this correspondence may be continued to higher and 

 lower temperatures, as I shall explain, after the following indi- 

 cation of the immediate effects observed on the hygrometer of 

 each increase of 1 grain at the three temperatures. In the 

 first two columns of the table, the points of the hygrometer 

 cease to be indicated at the period when dew appeared on the 

 side of the vessel. 



Table of mois- 

 ture indicated 

 by the hygro- 

 meter at differ- 

 ent tempera- 

 tures. 



Grs. of water ^^°"'^'°^^^'^ Points of the 



in 1 cubic foot, ^y^'- fL^'^'p- ^y^'- ^^o ^^"p- 



50^ 



a 

 15-2 



29'9 

 51-6 



74-9 

 S9'6 



55^ 



o 

 14-5 

 28-5 

 47-2 

 64-1 

 78-6 

 93-9 



Points of the 



hygr, at temp. 



60°. 



a 

 13'9 

 27-6 

 43-2 

 55- 

 68-3 

 82-1 

 96-6 



3R.emarks on 

 this table. 



23. This table shows the progress of the effects on the hy- 

 grometer of the evaporation of the successive grains of water. 

 These increases were stopped, as 1 have said above, by some 

 water being deposited on the sides of the vessel. This effect 

 took place for the 6th grain with the temperature 50°, and 

 for the 7th graifi at 55® : however, this happened only when 

 the grains were entirely evaporated, during which time the 

 hygrometer had moved j but there was no fixed point to be ob- 

 tained correspondent to the new grain of water, since a part of 

 it at last was deposited on the sides of the vessel. 

 Account of the 24. The tables which follow this, in my work, serre to com- 

 bine these results, by the rules of interpolation, for obtaining 

 the intermediate terms xtot given by the experiments j and also 

 to continue the same series, on one side, up to 98 of the ther- 

 mometer, and on the other, for a particular purpose, down to O. 

 The table ix,, which is the result of all these combinations, is 

 constructed in such a manner, as to afford immediately the an- 

 swer to the following questions, very important in meteorology. 

 1. A point having been observed on the hygrometer in the 



©pen 



other tables in 

 the work. 



Questions an- 



