of the prismatic Colours to heat and illuminate Objects. 259 



No. 1. No. 2. 



43 " " - 43 

 45i - - - 43 

 46 - - - 43 



46 - - ' - 42-! 



4 6 4 2 i 



Therefore, in ten minutes, the green rays occasioned a rise of 

 3 J degrees. 



4/£ Experiment. I now exposed my thermometer to the violet 

 rays, and compared it with No. 2. 



No. 1. No. 2. 



44 - - 44 

 44 ' - 44 

 44i - 432- 



45 - - - 43 



Here we have a rising of 2 degrees, in ten minutes, for the 

 violet rays. 



5th Experiment. I now exposed Dr. Wilson's thermometer 

 No. 2 to the red rays, and compared its progress with No. 3. 



No. 2. No. 3. 



44 - - - 44 



46 - - - 44 



4 6 i - 43* 



4<% - 43 3 



4- 



degrees 





Here the thermometer, exposed to red, rose in five minutes 2 J 



grees. 



6th Experiment. In red rays again, 



