228 Priestley and Ever shed. — Growth Studies. I. 
together with full notes as to weather conditions during the time of the 
experiment. 
Table I. Tradescantia , Series I (see Fig. i). 
Number of 
Mean wet weight 
Mean dry weight 
days' growth. 
of roots. 
of roots. 
grm. 
grm. 
9 
0.07 + 0.01 
0.004 + 0-001 
1 1 
0-15 ±0-01 
0-009 + 0-002 
12 
0.17 ±0.03 
O-OIl +0-002 
13 
0-19 + 0.03 
0-015 ±0.003 
. ] 4 
0-2 I ±0.03 
O.OI8+O.0O3 
J 7 
0-21 +O.O4 
O.OI9 ±0.003 
19 
O.3I+O.O7 
0*02 3 ±0.004 
2 3 
0-42+0.10 
O.O4I ±0.009 
29 
0.36+0-10 
0-045 ±0-01 1 
Series II. In this series, the cuttings were grown separately in bottles 
of about 600 c.c. capacity. The bottles were filled with the three-salt 
Fig. 1. The increase in weight of roots on cuttings of Tradescantia. The dotted line gives the 
data for wet weight on a reduced scale. The arrow shows when secondary roots appeared. 
solution found by Shive (10) to be most suitable in his investigation of water- 
culture methods. Gram-molecular solutions were made up of potassium 
dihydrogen phosphate, magnesium sulphate, and calcium nitrate. These 
