360 F. B. GUTHRIE AND L. COHEN. 



which barley would not grow. Comparison of the man- 

 ganese content of this soil and of adjacent land in the same 

 paddock, on which barley grows satisfactorily, showed that 

 in the case of the bad land a higher percentage of man- 

 ganese was present. The quantities in both cases were 

 again small, but was larger in the bad soil both in the 

 fusion, hydrochloric and citric acid solutions. The amounts 

 soluble in hydrochloric acid were 0*038°/° in the good soil, 

 and 0*087°/° in the bad, the amounts soluble in citric acid 

 being 0*034f in the good soil, and 0*062 in the bad. Judg- 

 ing from these results alone, which is perhaps premature, 

 it would appear that couch grass is affected by a proportion 

 of manganese which has no appreciable effect upon barley. 



A further case of soil-poisoning probably due to man- 

 ganese, has been afforded by the examination of samples of 

 soil from the Experiment Farm at Bathurst, on which 

 wheat died down before reaching maturity. The soil on 

 which the crop died was found to contain *114°f Mn 3 4 

 (soluble in hydrochloric acid) as against *026°/° in soil from 

 the same paddock in which wheat grew normally. 



The sample of bad soil was found to contain small frag- 

 ments (1/10 gram to 1 gram in weight) of a manganiferous 

 iron compound of a black colour and very soft. 



