714 SEC. 14. METEOROLOGY. 



consequence, the globular vessel is emptied. The connexion of the burette 

 with the sand is closed during the operation of filling. 



The evaporating vessel has a surface area of one square decimetre. 



To exclude, as much as possible, the influence of the temperature, the 

 evaporating vessel is enveloped in some had conducting material. 



The sensitiveness of the instrument is so great that a little dry sand, or a 

 piece of blotting paper, or the fraction of a drop of water, put upon the surface 

 of the evaporating vessel is immediately indicated by the water column in the 

 burette. 



2903. Atmometer or Evaporometer, for determining the 

 quantity of water evaporating from the surfaces of waters as well 

 as from different sorts of soil. Prof. Prestel, Emden. 



Atmidometer with Hicks' Patent enamel Stem for 



measuring the rate of evaporation from water, ice, or snow. 



J. J. Hicks. 



The enamel stem has the divisions and figures in black on white enamel 

 which renders the reading easy and the scale incorrosible. 



2904. Apparatus for the direct determination of the tension 

 of aqueous vapour in the atmosphere, constructed in the year 

 1868 by Dr. Geissler, of Bonn, according to the instructions of the 

 late Prof. Schulze, professor of chemistry in Rostock. 



Prof, Matthiesscn, Rostock. 



The U-shaped tubes serve for the reception of the mercury. The absolute 

 vapour tension of the atmospheric air enclosed in the flask-shaped vessel is 

 directly determined, at the differential barometer, through absorption of the 

 vapour by concentrated sulphuric acid, which is introduced for that purpose. 



IX. OZONOMETERS. 



2904a. Smyth's Ozonometer, made of brass, lined with 

 sealing-wax, and provided with brass stop-cocks, invented by con- 

 tributor previous to ozonometer No. 2905. John Smyth, jun. 



29G4b. Smyth's Ozonometer, made of brass, lined with 

 glass, and provided with glass stopper to admit air, invented by 

 contributor previous to ozonometers Nos. 2904 and 2905. 



John Smyth, jun. 



2904c. Diagram showing the rough form of ozonometer and 

 aspirator used by contributor in his first experiments, August 

 1865. John Smyth, jun. 



2901d. Diagram showing the contributor's ozonometer con- 

 nected to Dr. Andrew's form of aspirator by means of which his 

 later experiments have been made. John Smyth, jun. 



