the Broad Bean and certain other Plants. 
General conclusions. 
i*o grm. or more H 3 B 0 3 per pot caused a depression in the dry weight, 
though o*5 grm. was harmful if applied as a top-dressing. Possibly o-i 
grm. was slightly beneficial, though lower dressings were ineffective. 
2. Borax was slightly more toxic than an equivalent amount of boric 
acid. 
The probable errors have been worked out in typical cases for both 
barley and broad beans grown in pot culture. With barley treated with 
a top-dressing of boric acid (Table VIII), the error for the green weight 
ranges from + 1-56 to + 0*24, and for the dry weight from + 0-67 to + 0*28. 
Table IX. 
Mean Green and Dry Weights of Barley grown in Pot Culture with 
Boric Acid or Borax containing equivalent Boron. (Quantities given in 
terms of H 3 B 0 3 .) 
Average 0/6 pots. 3 plants per pot} 
Top-dressed immediately after sozuing. Mar. 15- Aug. 5, 192 2. 
Boric Acid. 
Borax. 
per 
pot. 
Green IVt. 
Dry IVt. 
% Dry in 
Green. 
Green Wt. 
Dry Wt. 
% Dry in 
Green. 
grm. 
grm. 
grm. 
grm. 
grm. 
grm. 
1.0 
34‘63 
13-08 
37 * 7 o 
34-68 
13*48 
38*87 
o -5 
35 *oi 
18-65 
53 ’ 2 ° 
35‘ 2 5 
16-42 
46*58 
o* 1 
33 * 6,5 
21-49 2 
63-86 
32*71 
2 i *35 
65*27 
0*02 
30-48 
21-64 
7 o *99 
33*37 
22-71 
68*oo 
Control 
35*64 
_2 
35*64 
__2 
Table 
X. 
Nitrogen in Dry Matter. Broad Beans grown in Water Culture. 
Concentration 
Mar. 
10-May 17, 
April 2S-June 13, 
Sept. 3- 
-Oct. 17, 
H z BO v 
%A- 
1921. 
Actiial N. 
/N. 
1921. 
Actual N. 
1921. 
% N. Actual N. 
1 :5,000 
4*°4 
grm. 
0*22 
2 *94 
grm. 
0*20 
4*55 
grm. 
0*16 
1 : 25,000 
3* x 9 
0*36 
2-6 I 
0-21 
4 * 3 i 
°*23 
1 : 50,000 
.3*07 
0-41 
2* 6 
0*21 
4*41 
0*22 
1 :100.000 
3 * 3 i 
0*38 
2-6i 
0-22 
4 * 2.3 
0*18 
1 :500,000 
3*27 
0*36 
2.6i 
0*21 
4*24 
0*22 
1 : 2,500,000 
3*o 2 
0 ’38 
2*72 
0.2 3 
4*ii 
0-20 
1 : 12,500,000 
3 * 3 1 
0-38 
2*93 
0*19 
4*30 
0*22 
1 : 100,000,000 
Control 
3*08 
0-2 7 
3*42 
0-18 
— 
— 
3 * 4 i 
Q' 3 1 
3*48 
0-15 
4*35 
0*11 
1 Pots containing fewer than three plants were included in the mean, as they only occurred in 
heavily treated sets and were not caused by normal failure of germination. 
2 Figures not available or mean of two pots only through accident. 
