22 EXPERIMENT STATION RECORD. 



cultivated, and uncultivated lands at different dates, as determined by 

 H, Snyder, are also reported. 



The results of these observations and experiments are summarized 

 as follows: 



"(1) The water-holding and consequently diongbt-resistiug qualities of the soil are 

 increased by the addition of organic matter to the soil. 



" (2) The loss of water by evaporation from the surface of the soil must be regarded 

 as the prime factor in robbing the soil of its moisture. 



" (3) Anything that breaks the force of the wind may make the difference between 

 success and failure in growing crops by lessening the evaporation. 



" (4) Evaporation from the soil may be largely prevented by the use of a mulch on 

 the surface. 



" (5) The use of a mulch may sometimes increase the amount of water in the upper 

 1 foot of soil on 1 acre by 1,700 bbls., and it probably exerts as much influence ou 

 the several upper feet of soil. As the roots of corn and most other vigorous plants 

 penetrate several feet into the soil, the increase due to a covering of mulch must be 

 considerable. 



** (6) It will be found that a circular plat of land 6 feet in diameter that is mulched 

 may have the water it contains increased in a period of drought by 8 gallons in the 

 upper 2 feet of soil. This indicates the great value of a mulch around street trees. 



"(7) The use of a mulch ou many garden crops will often make the difference 

 between success and failure." 



Investigations on nitrification, E. Godlewski {Anzieg. Akod. 

 KraMu, Dec, 1892; abs. in Centhl. agr. Chem., 22 {1893), No. 12, 

 pp. 848-851, and in Jour. Assoc. Anc. Elev. Gemhloux, 4 {1894), No. 8, 

 pp. 269, 270). — Experiments to determine whether the organisms of 

 fermentation derive their carbon from mineral substances, as claimed 

 by Winogradsky, or are dependent upon the volatile organic sub- 

 stances of the air absorbed by the nutrient solution, as suggested by 

 Elfving, are reported in detail. The conclusions reached are that — 



(1) It is very imj^robable that the nitromonas derive their carbon 

 from the organic substances of the air. 



(2) Nitromonas placed in a pure mineral solution are not able to 

 assimilate the carbon of magiiesinm carbonate. 



(3) It is very probable that these organisms find the carbon which 

 they need in the free carbonic acid or in the carbonic acid of bicarbon- 

 ates. 



These investigations also confirm the opinion widely entertained 

 that free nitrogen is formed during nitrification. 



The author suggests that the nitromonas find in the oxidation of 

 ammonia a source of energy sufficient to enable them to accomijlish the 

 dissociation of carbonic acid. 



Methods of soil analysis, F. H. Werenskiold {Bpt. Chem. 

 Control Sta. Christiania, 1893, pp. 21, 30). — The solution is prepared by 

 digesting 150 gm. of fine soil with 500 cc. of 10 per cent HOI in the 

 cold for 48 hours with frequent shaking (carbonates that may be pres- 

 ent are previously saturated with HCl). The solution is filtered through 

 a dry filter. 



Determination of lime. — Lime is determined in the filtrate in the fol- 

 lowing manner: 50 cc. (corresponding to 15 gm. of soil) are boiled in a 



