8 I. F. MCCLENDOX : I'ARAFFINE BATH FOR INDIVIDUAL USE. 



able size and shape for sinking receptacles for imbedding dishes, 

 paraffine pitchers, etc. For holding small vials I sunk larger ones 

 through the wooden top and filled the space between the two with 

 lubricating oil to prevent cooling by currents of air when the 

 bath was opened. A flat tile would be useful to cover each side 

 of the bath, avoiding the lamp socket. 



The temperature regulation is more perfect than in any other 

 small bath I have seen. The heat of the lamp melts the adjacent 

 parafline until the radiation equals the heat supplied, and con- 

 vection currents keep the melted portion at constant temperature. 

 When the temperature of the room rises, more of the paraffine 

 in the trough melts and increases the radiating surface. When 

 the temperature of the room falls, part of this paraffine congeals 

 and decreases the radiating surface. The paraffine in the imbed- 

 ding dishes is always kept melted unless they have been set too 

 deep or too far from the light. The bath is intended to be fire- 

 proof, but if space is the determining factor it should be made of 

 metal, in which case a higher candle power lamp should be used. 

 The trough might be made of glazed earthenware with double 

 side walls, the spaces between these walls opening downward and 

 the outer walls projecting below the bottom of the bath, thus in- 

 suring an air space beneath. 



Zoological Laboratory, 

 University ok Missouri. 



