Rate of Growth of Plants in Water Culture . 
9i 
Series 1. 
Cultures started February 10. 
Solutions changed February 13, 17, so, 24, 28, March 5, 7, 11. 
Cultures harvested March 14. 
Mean 
Probable error of mean 
Concentration of nutrient solution. 
I. 
1 
S’* 
1 
lU* 
1 
20* 
grm. 
grm. 
grm. 
grm. 
0*0439 
0*0594 
0*0316 
0*0279 
0*0460 
0*0604 
o*° 4 T 4 
0*0406 
0*0466 
0*0630 
0*0438 
0*0463 
0*0493 
0*0633 
0*0484 
0*0524 
0*0500 
0*0678 
0*0494 
0*0576 
0*0566 
0*0734 
0*0594 
0*0657 
0*0590 
0*0796 
0*0604 
0*0739 
0*0696 
0*0834 
0*0678 
0*0751 
0*0743 
0*0848 
0*0766 
0*0814 
0*0992 
0*0878 
0*1122 
0*0834 
o*<05945 
0*0723 
0*0591 
0*0604 
0*0036 
0*0023 
0*0048 
0*0039 
Reviewing these results after the probable error is taken into con¬ 
sideration, it will be observed that there is not much appreciable difference 
between the mean dry weights of the plants growing in solutions of different 
concentration. 
A series was grown during the spring in which Barley was employed as 
the culture plant. Seed of a pure line was used which was kindly sent by 
Professor Biffen to Professor Priestley. The growth of these plants was 
much more rapid than that of the Rye grown earlier in the year. The 
weights of the shoot and root of each plant were taken separately. The 
results of this series are as follows : 
Series 2. 
Cultures started April 28. 
Solutions changed May 5, 8, 13, 18, 22, 2 6, 29, June 2. 
Cultures harvested June 6 . 
Concentration — 1. 
Shoot. Root. Total, 
grm. grm. grm. 
0*319 0*078 0.397 
0*341 0*083 0*424 
0*369 0*096 0*465 
0*387 o*i 06 0*493 
0*476 0*128 0*605 1 
0*531 o*i22 0*653 
0*576 0*140 0*716 
0*592 0*146 0*739 
0*586 0*155 0*741 
0*838 0*208 1*046 
Mean 0*502 0*126 0*628 
Probable error of mean 0*041 
Dry weight of shoot 
- * - ■ —■—-- =: 
Dry weight of root 
1 In all cases the plants were weighed to a tenth of a milligram, but the numbers are here given 
correct to the third decimal place. 
