1885.] 



A bsorption-spectra Thermograms. 



81 



Fig. 2. 



Curve I. Naked incandescence lamp. 

 Curve VI. Absorption of empty cell. 

 Curve VII. „ of cell and |-inch of benzene. 



Curve VIII. „ „ ^-incli iodine solution in alcohol. 



Curve IX. „ „ „ sodium chloride saturated solution 



in water. 



Curve X. „ „ „ water. 



Curve XI. „ „ „ iodine in an aqueous solution of 



potassium iodide. 



Curve XII. „ „ iodine in carbon disulphide. 



water, as the curve shows the same qualitative absorption as Curve 

 No. 10, which is that due to -|--mch of water, the absorption being equi- 

 valent to what would have been produced by a diminished thickness 

 of water. This is a fact of some importance theoretically, and has 

 been confirmed by experiments with other solutions. 



Curve XI is that due to the absorption of iodine in an aqueous 

 solution of potassium iodide. Compared with Curve X it shows that 

 the molecular structure of potassium iodide is such that it intensifies 

 the absorption due to water alone, no trace of the spectrum being 

 found beyond Scale No. 14. 



Curve XII is the thermogram of the absorption-spectrum of a solu- 

 VOL. XXXVIII. G 



