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Microbes and You 



cial glass is ground up very fine, placed in molds, and heated just 

 to the point where the glass particles adhere to each other, leaving 

 pore spaces through which liquids may pass. The fineness of the 

 filters is directly correlated with the size of the glass particles 



Fig. 18. Sintered glass filter. 

 Corning, New York.) 



(Courtesy of Corning Glass Works, 



employed in their manufacture. Cleaning such sintered glass is 

 accomplished by passing sulfuric acid containing 1% sodium nitrate 

 through the filter. Bichromate cleaning fluid should be avoided 

 since it is adsorbed on the glass and may adversely affect future 

 filtrates. 



