June IS, igis Antagofiism between Anions as Affecting Barley 207 



On the other hand, the increased toxicity which follows the points of 

 antagonism is much more sharply marked in the series immediately 

 under discussion, and only 0.15 per cent of sodium carbonate need be 

 added to 0.2 per cent of sodium chlorid to depress the yield to the point 

 to which it takes an addition of 0.25 per cent of sodium sulphate to 

 0.2 per cent of sodium chlorid to depress it. 



In the case of the second crop, data of very similar nature to those of 

 the foregoing series are noted. The addition of even small quantities 

 (0.05 per cent) of sodium carbonate to 0.2 per cent of sodium chlorid is 

 instrumental in bringing about noticeably better growth, whereas markedly 

 higher results are obtained when amounts of sodium carbonate equiva- 

 lent to 0.1 per cent of the dry weight of the soil are added to 0.2 percent 

 of sodium chlorid. The maximum yield is obtained in No. 6, in which 

 the total dry matter produced is even greater than that of the control pots. 

 Even the addition of 0.3 per cent of sodium carbonate produces marked 

 antagonism to the sodium chlorid and allows a good yield. The data in 

 this series are therefore even more emphatically in support of the 

 existence of antagonism between anions than those of the foregoing 

 series involving the interaction of sodium chlorid and sodium sulphate. 

 Thus, again, an increase in the total alkali content of the soils from 0.2 

 to 0.5 per cent by the addition of 0.3 per cent of sodium carbonate to 0.2 

 per cent of sodium chlorid, so far from rendering the soil a much 

 poorer medium for plant growth, has made it even better than the control 

 soils containing no salt, and nearly twice as good a producer as the same 

 soil containing the same quantity of sodium chlorid but no sodium 

 carbonate. 



ANTAGONISM BETWEEN SODIUM CARBONATE AND SODIUM SULPHATE 



The arrangement of this series was similar to that of the preceding 

 series, sodium carbonate, however, being used as the constant toxic salt 

 and sodium sulphate being used in varying quantities for purposes of 

 antagonism. The results follow in Table IV. 



This is the only series of those submitted in this paper which gives no 

 proof of antagonism between anions when two salts are mixed. Appar- 

 ently there seems to be antagonism in this series not only in the case of 

 the second crop, as in the foregoing series, but also in the case of the first 

 crop. In reality, however, this is not so, as can be seen by an examina- 

 tion of the data submitted in Table I. From the latter we see that 

 the assumed toxicity of culture medium 2 of Table IV is greater than 

 that of any other of the toxicity series forsodium carbonate, even where 

 twice as much sodium carbonate is employed. While, therefore, there 

 may be an actual antagonism between sodium carbonate and sodium 

 sulphate, the evidence of it in Table IV is absolutely untrustworthy, and 

 largely for the reason that no quantity of sodium carbonate employed 

 has actually been shown to be definitely toxic to barley in the clay-adobe 



