637 



inrreased. The proportion of ammoniacal nitrogen, however, was not 

 appreciably increased in the soils containing 2 or 3 gr. of organic nitro- 

 gen as compared witli those containing only 1 gr. per kg., and con- 

 se(inently the absolnte amonnt of ammonia prodnced was larger in the 

 former soils. 



The following i)ra('tical conclnsions are drawn from these experiments: 



(1) Jf it is desired in the preparation of composts to transform nitrog- 

 enous organic matter into nitrate, the mixture should not (contain over 

 1 gr. of nitrogen per kg. Thirty per cent of clay or marl and 0.5 per 

 cent of plaster may be added. The compost will then be in a favorable 

 condition to fix atmospheric nitrogen. 



(2) If the production of ammoniacal nitrogen is desired, the amount 

 of organic nitrogen per kg. of compost may be increased to 2 or 3 gr. or 

 even more. From 10 to 40 per cent of marl and 0.5 to 1 per cent of 

 l)laster may be added. 



(3) In soils where there is no danger of arresting nitrification by the 

 formation of a medium which is too ammoniacal it will be useful to 

 increase the amount of lime or to use unslaked lime in combination with 

 plaster. 



Recent observations on the amount of sulphur in arable soil 

 and on the nature of the compounds which it forms, Berthelot 

 and Andre {Cowpt. rend, 114 {1893), pp. 43-46).— In connection with 

 researches regarding the formation of sulphur compounds in plants 

 (see Annales de Chimie, ser. 6, torn, xv, p. 124) the authors made 

 some observations on sulphur in arable soil. The soil in which the 

 plants were grown contained per kg. of dry earth 0.372 gr. of sulphur 

 (total) and 0.1G9 gr. of sulphate. Treatment with a potash solution 

 (boiling) gave 0.357 gr. of sulphur in the soluble portion and 0.023 gr. 

 in the insoluble portion. The total sulphur, 0.38 gr., did not materially 

 differ in amount from that given above. The potash solution did not 

 entirely decompose the sulphate in' the soil, for the liquid filtrated after 

 this reaction contained 0.114 gr. of sulphate (after potash without heat) 

 and 0.139 gr. (after potash with heat), whereas the total sulphate was 

 0.100 gr. 



The organic sulphur in this soil was 0.372-0.169=0.203 gr.; the 

 organic nitrogen 2.350 gr. In another soil containing 1.17 gr. of total 

 sulphur the organic sulphur was 0.01 gr. and the nitrogen 1.07 gr. In 

 the former case, therefore, the percentage of organic sulphur as com- 

 pared with nitrogen was 8.7; in the latter 36.5. The latter soil also 

 contained 19.1 gr. of organic carbon. In animal albuminoids (albumin 

 and Hbrin for example) the percentage of sulphur is 10 to 11, while in 

 horny substances it is about 20. In animal organisms in general, as 

 analyzed by Bidder and Schmidt, the percentage was about 7. 



But this mode of comparison is not snflQciently wide. In arable soil, 

 generally speaking, the relation between organic carbon and nitrogen 

 by weight is entirely different from that in albuminoids and animal 



