Dr Gardner on the Action of Light on Vegetables, 



89 



Table, shewing the Force of the Solar Bays in producing the 

 Green Colour of Plants^ the Decomposition of Carbonic Acid^ 

 and Illumination. 



Upon projecting these numbers, which, although not rigor- 

 ously correct, are very good approximations, the unity of the 

 active agent will be more strikingly exhibited. Let the axis 

 of abscissus be divided into intervals corresponding to Fraun- 

 hofer's coloured spaces, and the positions of the mean places of 

 the dark lines be marked from Powell's recent work on Disper- 

 pion. The ordinates are from the table. Fraunhofer's esti- 

 mates are indicated by a bold line, Dr Draper's by dots, and 

 jTiy own by an interrupted line, fig. 1. 



<«u p W Ph O 



Had more points in these figures been determined, there is 

 no doubt they would have coincided precisely. It is not to be 

 forgotten, that these results were obtained in places many hun- 

 dred miles apart. They determine, what hitherto has only 



