132 



THE FLOATING-MATTER OF THE AIR. 



The chambers, being closely sealed, were permitted to 

 remain undisturbed for a few days. The floating 

 matter of the internal air gradually subsided, until at 

 length an intensely luminous beam failed to show its 



track within the chamber. Then, and not till then, 

 were the infusions introduced, by means of a pipette 

 passing through the top of the chamber. After their 

 introduction, they were boiled in an oil or brine-bath ' 



' From the fact of their being boiled in oil or brine, Professor 



