Flame Reactions of Thallium. 169 
CONCLUSIONS. 
Thallous chloride, when introduced in the Bunsen flame, dissociates, 
yielding the metal. This metal can be condensed on a cold object in 
the form of a brownish mirror. The characteristic luminescence of the 
flame is to be traced to the existence of the free metal in it. 
When the hydrogen-air flame is charged with the vapor of thallous 
chloride, five different zones, each distinguishable by a different lumi- 
nescence, can be observed. A lustrous metallic mirror of a brownish 
tinge can be obtained on a cold object by depressing the inner cone of 
the flame. The luminescence here again is to be traced to the element 
thallium. No deposit of thallium is obtained when the cold object is 
introduced in the outer zone; the luminescence in this region is undoubt- 
edly due to the formation of an oxide or oxides of thallium. 
