392 F. B. GUTHRIE AND R. HELMS. 



In Nos. 93 and 94, the plants had recovered and were 

 apparently as healthy as the control pots, whereas in Pot 

 No. 95 the growth was affected. 



From the above it is concluded that the germination of 

 barley is affected by about *1 per cent. NaOl, and entirely 

 prevented by the presence of *25 per cent. The growth is 

 affected by as little as *07 per cent. NaOl, but with this 

 quantity and up to '15 or "20 per cent, the plants may 

 recover under favourable conditions. With *20 per cent. 

 the growth is prevented. 



Experiments with sodium carbonate. 

 Eight pots were tilled with soil, manured with super- 

 phosphate and sown on December 3rd, 1902, with 13 grains 

 of barley. Sodium carbonate had previously been added in 

 the following proportions: — 



No. 90, *1 per cent, Na 2 Co 3 



9 



II l ' l -° it M 



„ 99, '30 „ 



„ 100, '35 „ 



„ 101, -to „ 



„ 102, '50 „ 



„ 103, '60 „ 



The appearance of these pots on December 13th, when 

 they were examined was as folLows : — 



Germination had not been affected in pots 96 and 97. 

 In pot 98 the germination had been slightly retarded, 



though all the seeds had germinated. 

 In the remaining pots the germination was less vigorous 



and in pot 103 the seeds did not germinate at all. 



In pot 96, the plants were growing well. In 97 the 

 growth was slightly affected, the effect increasing with 

 increase of sodium carbonate up to pot 101. In this and the 

 succeeding pots the plants had died. 



