FERTILIZERS. 727 



(1) Xatural, including surface or l)road irri^'atioii, and (2) artificial, including (a) 

 prccii)itation or chemical nieth(xl, (h) intermittent downward filtration, and (c) 

 bacteriolysis or the bacterial treatment. The first is considered "entirely impracti- 

 cable for large jiopulous centers" on ai-count of its large cost, failure in time of frost 

 and heavy rainfall, and liability to become malodorous in warm weather. 



"With reference to sewage farms, it may be said with absolute correctness that, 

 with everything else equal, they fail without the closest supervision. With that, 

 however, added to the other conditions, such as suitable land, etc., they may be 

 worked up to a high pitch of efficiency." 



Analyses are reported which show that wet, compressed, and compressed and 

 steam-dried sludge obtained by precipitation by lime have a comparatively low fer- 

 tilizing value, the compressed sludge containing only 0.788 per cent nitrogen, which 

 increa.«es to 1.73-1.9 per cent when the sludge is steam-dried. The material contains 

 very small amounts of phosphoric acid. "By the addition of chemical constituents 

 it could be made a vahial)le manure." 



The reduction of nitrates in tlie presence of barnyard manure, J. P. Street 

 {Xew Jersey Stas. Rpt. 1900, pp. 7D-SS). — The experiments here reported were a 

 continuation of those of the previous year (E. S. R. , 12, p. 321) and were conducted 

 in the same manner except that loosely covered -100 cc. beakers were used instead of 

 flasks, and a mixture of solid and liquid excrement was emjiloyed instead of solid 

 manure alone. In one series 30 gm. of the mixture was placed in each beaker alone 

 and with the addition of sodium nitrate alone at the rate of 83 lbs. per ton of manure, 

 or with acid phosphate, kainit, gypsum, iron sulphate, and potassium sulphate, each 

 at the rate of 26 lbs. per ton, and glucose, wheat straw, and pine shavings each at the 

 rate of 133 lbs. per t(^n. In a second series ammonium sulphate alone or combined 

 with acid phosphate, kainit, gypsum, and iron sulphate was substituted for the sodium 

 nitrate. The experiments began January 22 and continued 33 days, the changes in 

 ammonia, nitrates, and insoluble nitrogen being determined at 4 different periods. At 

 the end of the experiment the nitrates had entirely disappeared in the tests in which 

 glucose, straw, and shavings had been used. The loss where iron sulphate was used 

 was 7.9 per cent less than where nitrate was used alone (without preservatives). 

 "Acid phosphate and kainit seemed to have a slightly favorable effect, while plaster 

 and sulphate of potash caused no additional loss." There was an increase of insol- 

 uble organic nitrogen in all of the tests, but this increase was apparently "smaller 

 where nitrate of soda was used alone, or in connection with superphosphate, kainit, 

 plaster, sulphate of iron, sulphate of potash, or shavings." With the straw there 

 was about the same gain as with manure alone, and with glucose about twice as 

 much. The results of the experiments with ammonium sulphate agreed closely 

 with those obtained the previous year except in case of gypsum, "which, in 1899, 

 was with sulphur the most effective preventive of loss used, but in 1900 was the least 

 efficacious." The loss of ammonia varied from 13.1 per cent with iron sulphate to 

 33.8 per cent with gypsum. There was a large gain of insoluble organic nitrogen in 

 these experiments, varying from 34 per cent where manure was used alone to 102.7 per 

 cent where manure was used in connecti(m with ammonium .sulphate and gypsum. 



Investigations relative to the use of nitrogenous materials, E. B. Voorhees 

 (AVw Jersey Stas. Rpt. 1900, pp. 88-110). — A continuation of experiments of the pre- 

 vious year (E. S. R., 12, p. 322) is here reported. The composition of the solid and 

 mixed solid and licjuid excrement of a cow in the fresh condition and after exposure 

 to natural leachuig from February 3 to April 13 (70 days) was found to be as 

 follows: 



21164— No. 8—02 3 



