﻿Ultra-violet Liglit on Chlorine. 7G1 



Table of Wave-lengths in the Ultra-violet Region. 



Wave-length. 





Description 

 and 



Remarks. 



M* 





abbreviation. 





440—380 





Violet. 



Visible. 



380—340 





Glass 



Passes through ordinary glass 







Ultra-violet 



(in fairly thin layers); Carbon 







(Glass-violet). 



arc rich source. 



340—300 



as 



Jena glas3 



Passes through Jena ultra-violet 





o 



Ultra-violet 



crown glass ; strongly emitted 





> 



(Jena-glass * 



by the Uviol Mercury lamp. 





N 



violet). 





300-220 



e3 



Qnnrtz-glass 



Passes through fused silica (and 





3 

 cr 1 



Ultra-violet 



calc-spar) in fairly thin layers : 





c5 



(Quartz-glass* 



last portion of strong radiation 





Sh 



violet). 



from the Quartz Mercury and 





HH 





Amalgam lamps. 



220—180 





Quartz- crystal 



Passes through crystallized quartz. 







Lltra-violet 



gypsum, rock-salt in fairly thin 







(Crystal-violet). 



layers : separable in the quartz- 

 spectrograph. 



180 -J 20 



-tJ 



Fluorspar 



Passes through good fluorspar, 





<D 



Ultra-violet 



but completely absorbed by a 





c 



(Schumann- 



short space of air ; separable in 





> 



violet). 



a vacuum — fluorspar — spectro- 





si 





graph. 



120—90 (?) 



03 



Reflex ultra- 



On the dispersion theory strongly 





3 



violet 



reflected by the above media : 





C7 1 



(Reflex violet). 



separable by means of a reflexioi i 









grating. 



Shorter waves 



EH 



Trans-reflex 



Violet. 





* The^e two radiatirns are by no means sharply separated by the absorption 

 of fused quartz, this absorption increasing very gradually in the region of 

 220 fifx ; nevertheless, it may be convenient to reserve separate names for the 

 two portions of quartz-violet. 



In early experiments the chlorine was obtained respecti vely 

 from chlorine water, bleaching powder and sulphuric acid 

 and by the electrolysis of cnpric chloride solution, but 

 finally the gas was obtained from liquid chlorine in a steel 

 cylinder. 



The gas was dried by passage first over calcium chloride, 

 then over phosphorus pentoxide on broken glass, and finally 



