78 FRAGMENTS OF SCIENCE. 
act of the molecule as a whole, that it could continue to 
affect waves of the same period after the substance had 
passed from the vaporous to the liquid state. 
In point of fact, the decomposition of the nitrite of amyl 
is itself to some extent an illustration of this internal 
molecular absorption; for were the absorption the act of 
the molecule as a whole, the relative motions of its con- 
stituent atoms would remain unchanged, and there would 
be no mechanical cause for their separation. It is probably 
the synchronism of the vibrations of one portion of the 
molecule with the incident waves, that enables the ampli- 
tude of those vibrations to augment, until the chain 
which binds the parts of the molecule together is snapped 
asunder. 
I anticipate wide, if not entire, generality for the fact 
that a liquid and its vapor absorb the same rays. A cell 
of liquid chlorine would, I imagine, deprive light more ef- 
fectually of its power of causing chlorine and hydrogen to 
combine than any other filter of the luminous rays. The 
rays which give chlorine its color have nothing to do with 
this combination, those that are absorbed by the chlorine 
being the really effective rays. A highly sensitive bulb, 
containing chlorine and hydrogen, in the exact proportions 
necessary for the formation of hydrochloric acid, was 
placed at one end of an experimental tube, the beam of the 
electric lamp being sent through it from the other. The 
bulb did not explode when the tube was filled with chlorine, 
while the explosion was violent and immediate when the 
tube was filled with air. I anticipate for the liquid chlo- 
rine an action similar to, but still more energetic than that 
exhibited by the gas. If this should prove to be the case, 
it will favor the view that chlorine itself is molecular, and 
not monatomic. 
Production of Sky-blue by the Decomposition of Nitrite 
of Amyl. 
"When the quantity of nitrite vapor is considerable, and 
the light intense, the chemical action is exceedingly rapid, 
the particles precipitated being so large as to whiten the lu- 
minous beam. Not so, however, when a well-mixed and 
highly attenuated vapor fills the experimental tube. The 
effect now to be described was first obtained when the 
