424 EXPERIMENT STATION EECOED. 



23.03 per cent sand and matter insoluble in hydrochloric acid, 2.64 and 4.04 per 

 cent phosphoric acid, 4.87 and 11.1 per cent lime, 2.51 and 2.26 per cent organic 

 nitrogen, and 3.05 and 2.74 per cent ammonia nitrogen. The first sample con- 

 tained 0.26 per cent potash. 



In sand culture experiments with wheat to determine the value of the organic 

 matter in the sludge, in which the different soluble constituents of the sludge 

 were separated and used in solutions to water the wheat plants, it was found 

 that the aqueous extract of the dried sludge fertilizer had a very marked bene- 

 ficial action upon plant development, and that the soluble organic constituents 

 produced an effect equal in intensity to that of the dried sludge itself. Similar 

 experiments with septic tank sludge gave the same results. " The amount of 

 soluble matter in the Dickson fertilizer (without additions) was, however, 

 found to be about doul>le that in the specimen of tank sludge investigated. The 

 precipitated organic matter from the latter was also relatively smaller in 

 amount, had a mo.«!t unpleasant smell, and was of a darker color." 



The utilization of town sewage for the manufacture of ammonium sul- 

 phate, A. A. Kaluzhskii (Iz RezuVt. Vcgct. Opytov Lab. Rabot, 9 (1913), pp. 

 253-358, pis. 7, figs. 2). — Laboratory experiments with municipal sewage to 

 determine its value as a source of ammonium sulphate are reported. 



Ammonia was obtained by treatment of the whole sewage with calcium hy- 

 droxid and boiling or steaming. The greatest quantity of nitrogen was present 

 as volatile ammonia (43.7 per cent), followed in order by the nitrogen of or- 

 ganic compounds of the sludge and the nitrogen combined in the liquid sewage. 

 The remaining quantities of nitrogen were about equally distributed between 

 the combined and uncombined ammonia of the sludge and the organic compounds 

 dissolved in the liquid sewage. 



There was no important loss of nitrogen from the sewage when kept air-tight 

 for three months. When kept in open tanks nitrogen losses were observed after 

 four days, which steadily increased to 07.76 per cent after three months. 



It was found by a series of distillation experiments that on the average about 

 9.06 kg. of ammonium sulphate could be prepared from 1 cubic meter of the 

 whole sewage. Of the total nitrogen extracted by lime more than half (58.4 per 

 cent) was volatile ammonia, 30.29 per cent was combined ammonia, and the 

 remaining quantity (5.31 per cent) was obtained from organic compounds. Pro- 

 gressive extraction of the ammonia gave larger amounts than imniediato total 

 extraction. The different heating methods used exercised no marked inlluence 

 on the amounts of ammonia extracted. While the speed of the ammonia extrac- 

 tion differed widely for the different methods of heating used, the general 

 character of the processes was the same. 



On distillation with calcium oxid the ammonia separation began immediately, 

 although in small amounts. The separation of volatile ammonia before the 

 addition of lime was observed only after heating to the boiling point. For a 

 maximum extraction of ammonia from the liquid from 10 to 12.5 gm. of lime per 

 liter of liquid was necessary by the innnediate total extraction method, while by 

 progressive extraction only 5 gm. of lime was needed. One cubic meter of the 

 sewage after extraction of ammonia with calcium hydroxid yielded 33 kg. of 

 sludge which contained 1.5 per cent nitrogen, from 2 to 3 per cent phosphoric 

 acid, and approximately 30 per cent calcium oxid. 



On the basis of the results obtained it is concluded that the manufacture of 

 ammonium sulphate from municipal sewage of similar composition is economi- 

 cally jirotltable. 



The phosphate deposits of Florida, G. C. Matson (U. .9. Oeol. Survey Bui. 

 GOff {1915). pp. 101, pis. 17, figs. 2).— This report deals with the geologj-. 

 mineralogy, origin, composition, and mining of the phosphate deposits of Florida. 



