Figure 3. — Dolland's "atmospheric recorder": i, siphon and float barometer; 2, balance (?) 

 thermometer; 3, hygrometer; 4, electrometer; 5, float rain gauge; 6, float evaporimeter; 7, 

 suspended-weight wind force indicator; 8, wind direction indicator; g, clock; 10, receivers for 

 rain gauge and evaporimeter. (From Official . . . Catalogue oj the Great Exhibition, 1851, 

 London, 1851, pt. 2). 



