78 FRA GMENTS 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 

 bo 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. 



\Vhen 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 



