ABSOLUTE AND KELATIVE HUMIDITY. 



Helailve Moisture at tlie above stations in the same periods. 



Drassels' 



St. Petersburg*.. 



Pekias 



Tiflis< 



Sitka6 



227 



75.2 

 81.8 

 C3. 8 

 67.0 



83.8 



1 From Quetelt's Meteorologie de la Belgie. Periocl, 1843-1862. 



2 Latitude, 59° 56' ; longitude, 30° 16' east ; elevation, 4.5 meters. Period, 33 years. 



3 Latitude, 39° 57' ; longitude, 116° 29' east ; elevation, 32 (?) meters. Period, 1850-1855. 



* Period, December 1, 1861, to December 1, 1871. 



* Period, 22 years while Kussian territory. 



These quantities are represented by graphic drawings in the accom- 

 panying figures. 



Absolute Humidity tbrough the several months of I Eehitivo Humidity through the several months of 

 the year at various foreign stations. | the year at various foreign stations. 



It will be observed that the scale of absolute humidity, on an average 

 of several years, is remarkably regular, with its minimum in January or 

 February, and its maximum in June or July. The rise in summer is ex- 

 cessive at Pekin and least at Tiflis. When reduced to a diagram, 

 Brussels and St. Petersburg appear nearly coincident. The range for 

 Tiflis is relatively very low, and the maximum for Sitka is carried for- 

 ward into August. 



The elastic form of vapor being increased by heat, we should expect 

 to find the summer range highest in hot seasons, and that differences 

 would be observed between years, corresponding with those of mean 

 temperature. This, in fact, is observed on comparing records, and re- 

 ducing them to graphic form in the tables. 



The relative humidity is found to be influenced very much by the 

 prevailing wind. In the Atlantic States, an easterly wind blowing 

 several hours invariably brings an increase of humidity, more especially 

 in winter, while northerly winds, as a general rule, cause a reduction of 

 the percentage of moisture. 



It is observed that as the sea is always of uniform height — opposing 

 no resistance to the winds in one place more than in another, and with 



