10 ABSORPTION AND EXCRETION OF SALTS BY ROOTS. 
ments showed that this water was measurably improved as a culture 
medium by a double redistillation according to the method of Rich- 
ards,! i. e., by using water-seal connections between Jena glass boilers 
and block-tin condensers. It was distilled first from alkaline and 
then from acid potassium permanganate. In comparing the effect of 
the two kinds of water, the rate of elongation of the primary root was 
Fic. 3.—Seedlings of culture 8, experiment C. 
made the criterion. The average elongation for 24 peas during the 
first 24 hours was 12.6 mm. in thrice-distilled water, and 9.2 mm. in 
the laboratory water. The average elongation for 24 white lupines 
in thrice-distilled water during the first 24 hours was 18 mm., and 
during the second 24 hours 4 mm.—a total growth of 22 mm. in 48 
1 Richards, T. W. YTroceedings of the American Academy of Arts and Sciences, vol. 30, 1894, p. 380. 
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