UTAH ACADEMY OF SCIENCES 77 
which the roots descended upon germination, thus giv- 
ing an excellent lot of vigorous, uniform seedlings with 
serviceably straight radicals about two inches long. 
Ordinary glass tumblers, the sides of which were 
covered with black paper and the top by perforated par- 
affined paper, were used as containers. Ten plants were 
grown in each tumbler in most cases. Pfeffer’s nutrient 
solution and doubly distilled water with a specific con- 
ductivity of 2.064x10—* were used as the media. For the 
conductivity work a Wheatstone bridge—telephone appa- 
ratus was used. The temperature was controlled to 1/10 
degrees C. by use of a specially constructed water tank 
holding fifty gallons with a pilot flame underneath. 
3. RESULTS. 
If distilled water injures plants by reason of extract- 
ing nutrient materials, then it would be expected that 
greater injury would result if the distilled water were 
renewed or changed frequently during the time the organ- 
ism were in it by virtue of the increase in its extracting 
ability. To test this out, both peas and horse beans were 
grown in doubly distilled water forty-seven and forty-five 
days respectively. For half of the cultures the water was 
replaced by fresh water every four days. The water 
for the other half of the cultures was not renewed, tho 
the small loss by transpiration and evaporation was made 
up in order to maintain a constant level in the tumbler. 
The results obtained at the end of the period are shown 
in Table I. 
