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VOLUME 21 

 NUMBER 12 

 DECEMBER, 1918 



CONTAINING 



The Effect of Ions of NaCl and CaCla Upon the Electrical Conductivity of 

 Certain Colloidal Mixtures. Newton Baldwin Green 303 



The Endemic Palms of Hawaii: Pritchardia. Vaughan MacCaughey 317 



Books and Current Literature 329 



Notes and Comment 332 



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Entered as <iccond-olaa8 matter March 9, 1912, at the poet office at Baltimore, Maryland, uuder the act of July IS, 1804 



