THE USE OF WEATHER INSTRUMENTS 



185 





FIG. 130. FIG. 131. FIG. 132. 



FIG. 130. A. Siphon barometer. B. Device for adjusting the barometer 

 tube so as to bring the surface of mercury in the cistern to the proper height. 

 FIG. 131. Fortin's pattern barometer. 

 FIG. 132. Sectional view of the cistern of a Fortin's pattern barometer. 



