Feb., 1916] Spectra of Some Ilalogefi Compounds 117 



Cadmium Iodide. 



Heat was applied slowly; numerous spectral lines appeared 

 together with what we concluded to be the same three bands 

 as found in zinc iodide, but as heat was applied the compound 

 quickly ceased to function — due doubtless to rapid vaporiza- 

 tion — and the air spectrum returned so quickly with each 

 increase of temperature up to the highest degree attainable 

 that no measurements could be made. 



II. Chlorides. 



Fused Stannic Chloride. 



Low heat gave a continuous region from 5800 to 4400 

 diffuse at both ends. The following lines were noted when the 

 salt was first heated: 6453, 5799, 5631, 5588, 5563, 5333 and 

 4525, due to tin and 5460 due to chlorine. 



It was found on the initial heating that the tin lines appeared 

 very prominent when the pressure was of the order of a centi- 

 meter of mercury, but that these lines disappeared in general 

 and the continuous spectrum named above appeared as the 

 pressure was reduced. With further experimentation this 

 pressure effect disappeared for reasons which will be suggested 

 in the concluding portions of this paper. 



Ferric Chloride. 



The continuous region, 5900-4800 Angstroms, was not 

 sharply defined at either limit. 



It was difficult to get a discharge to pass through the 

 tube containing the ferric chloride when it was heated. The 

 capillary filled readily with a brownish liquid which over- 

 flowed the ends of the rubber cork stoppers and operated to form 

 a conducting layer along the surface. 



After the disappearance of the air spectrum the character- 

 istic yellow and green lines of mercury and the red and blue 

 lines of hydrogen appeared.* With further heating a con- 

 tinuous region, indeterminate at both ends, occurred from 

 approximately 4800 to 5900. There was no evidence of any 

 iron lines at any period of the experimentation. 



*Mercury vapor and hydrogen were present as "impurities" in all these 

 experiments, the mercury coming from the McLeod guage used to measure 

 pressures. 



