SOI^UTION AND CRYSTALI^IZATION 



97 



crystal forming on these may be easily lifted out without breaking. 

 A veiy instructive and interesting method of forming crystals 

 is that of smearing a solution of a substance over the surface of a 

 clean sheet of glass. As the water evaporates the crystals may 





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FIf . GO. Sal amnnniac crystallizing on a sheet of glass. 



be seen to form over the surface of the glass. If the formation 

 of the crystals be oberved by means of a hand lens or under a low 



