FERTILIZERS. 875 



(11) By thorouo-li treatment of the manure with bisulphid of carbon 

 it was possibh^ to rcdnci' tlie (lenitrifying- power of tlic manure to a 

 minimum, but ou account of tlu^ amount' of bisulphid needed and the 

 time required tliis method of preserving- manure is considered vahieless 

 for practical purposes. 



(12) Sulphuric acid and copper sulphate were also found to be effect- 

 ive means of checking the action of the bacteria of the manure, but it 

 still remains to be proven whether they can be employed with advan- 

 tafte in practice. 



Contribution to the subject of the changes occurring in the 

 decomposition of nitrogenous organic substances, T. Pfeiffer, 

 E. Franke, C. GiVrzE, and II. Tiiurmann {Lamhc. Vers. Stat., 48 

 (1897), No. 3-5, pp. 189-245, pj. i).— The experiments here recorded in 

 detail were made on a mixture of solid cow excrement with ground 

 peat or with cattle urine in 5-liter flasks, similar to those described by 

 Dietzell in the article above (p. 872), or in zinc boxes capable of holding 

 7 or 8 kg. of the manure mixture. 



In the first experiment (with a mixture of cow excrement and i)eat) 

 4 series of tests were made. In the first series no preservative was 

 added, in the second 3 per cent of gypsum was added, in the third 3 

 per cent of gypsum and 1 per cent of double superphosphate, and in 

 the fourth 3 per cent of gypsum and 1 per cent of "precipitate." Four 

 flasks were used in each series. With 2 flasks the air was drawn over 

 the manure and with 2 it was drawn through the manure, 1 flask in 

 each case remaining in the experiment 5 months and 1 10 months. In 

 one zinc box the manure was packed close and in the other it was kept 

 loose, the experiments Avith these continuing for 5 months. 



In the second series of experiments a mixture of liquid manure, urea 

 solution, and ordinary or acidulated peat having about the composi- 

 tion of average barnyard manure was treated with from 0.3 to 1 per cent 

 of sulphuric acid, 0.5 to 1 per cent of water-soluble phosphoric acid 

 (double superphosphate), 0.1 to 0.3 per cent of potassium fluorid, and 

 O.o to 0.0 per cent of jiotassium chlorid. The preservatives were 

 applied either to the mixture or to the urea solution before mixing. 



In the third series of experiments the influence of sulphuric acid 

 and of a mixture of organic acids (butyric, capric, and caproic) either 

 alone or combined with causti<; lime or carbonate of lime upon the 

 (lenitrification in samples of fresh solid horse excrement to which a 

 nitrate solution (0.25 per cent) had been added were tested, the exi)eri- 

 ment lasting 30 days. 



Other exi)eriments are reported in which the influence of the tem- 

 perature (room temperature and 30 to 32° C.) on the jiroduction of 

 ammonia in mixtures of liquid manure, urine, and peat treated with 

 water-soluble phosphoric acid, caustic lime, calcium carbonate, and 

 butyric acid were tested. The influence of the exclusion of air and of 

 a liberal supply of air upon the nitrate nitrogen in fertilizer mixtures 

 was also studied, and comparative tests of nitrate of soda and the solid 



