Tea 
P 
Physics and Chemistry. 109 
alloys usually exhibit the lines characteristic of each constituent, but this 
18 not the case when one constituent is present in comparatively very 
small quantity. ‘Thus plumbago, containing 3°94 per cent of iron, gave 
a distinct iron-spectrum, but no indication of iron was observable in the 
n 
respond with those of Angstrém, Alter, and 
ch gas tinges the spark of a characteristic color; but no judg- 
ment can be formed from this color of the kind of spectrum which the 
gas will furnish. 
(2.) In most cases, in addition to the lines peculiar to the metal used 
as electrodes, new and special lines characteristic of the gas, if elementary, 
or of its constituents, if compound, are produced. When compound 
gases are employed, the special lines produced are not due to the com- 
pound as a whole, but to its constituents. 
(3.) The lines due to the gaseous medium are continuous, not inter- 
Tupted or broken into dots.—Journal of Chemical Society, [2], xi, 59. 
Ww. 
@ 
32 
rd 
@e 
# 
“4 
&. 
So 
3 
oe 
° 
= 
e 
2 
5 
= 
bo 
@ 
: 
baal 
o~ 
=. 
m7 
we 
=] 
se 
s 
® 
ct 
a 
oO 
Ss. 
=. 
” 
and one of the green. When the vapor is mixed with oxygen previously 
to its introduction into the flame, we obtain a spectrum of a brilliancy 
which the eye can scarcely support ; the violet rays appear with peculiar 
; : ; 
emi or colder according as moist or dry air was pass 
was true for plates of other metals. Finally, the results of a 
they are brought in contact with air containing less moisture than that 
: which they are placed. It further appears from the experiments of 
