->  JB> pretty much, the last time I looked close at a weet 
->  JB> thermometer it just has a hollow wick tied over the bulb 
->  JB> and dipped in a little tank of water 
 
-> that's what i've seen... if one has a fan blowing over it, does the tank nee 
-> to be covered with the wick poking up thru a hole? how much wick would be to 
-> much such that it was drying too fast in the fan blown wind and not getting  
-> the bulb? 
  
Ideally, the water in the tank would be at the same temperature as the 
wet bulb, so heat wouldn't be conducted from the tank to the bulb. So 
the tank should NOT be covered. Evaporation should be allowed from the 
surface of the water, keeping it cool. 
  
Trial and error would be needed to get the parameters right. 
  
And remember that the water must be very pure, and the wick should be 
frequently replaced or rinsed. 
  
                          dow 
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