CHEMISTRY. 331 



Determination of potash, N. Tarugi {Gaz. Chun. Ital., 34 {1904), I, pp. 324- 

 341; dbs. in Chem. Centbl., 1904, II, No. 4, p. 366).— Organic matter in about 1 gra. of 

 substance is destroyed by treatment with concentrated sulphuric acid, and hydro- 

 chloric acid, sulphuric acid, and ammonium salts arc removed by ignition. The 

 residue is dissolved in 10 cc. of water and the solution is mixed with 10 cc. of a 15 

 percent solution of sodium persulphate (Na 2 S 2 8 ) and placed in a thermostat until 

 its temperature becomes constant. 



The mixture is allowed to stand 3 hours at 0° C. for dilute solutions, at room tem- 

 perature for concentrated solutions, when by adding a small crystal of potassium 

 persulphate the potassium persulphate in the solution crystallizes out. The per- 

 sulphate content of 10 cc. of the clear supernatant solution is then determined by 

 means of tenth-normal sodium hydroxid and compared with that of the original 

 sodium persulphate solution used. The difference between the two, allowing for 

 dilution, multiplied by 0.0047 and corrected for potassium persulphate dissolved 

 (factors for which are given) represents potash present. Fairly satisfactory results 

 were obtained with the method. 



Different methods of mechanical analysis of soils and the method of double 

 sedimentation with a small sample, Rabanin (Poclivovyedenie [Pidologie], 5 (1903), 

 Nos. 1, 2; at ik. in Zhur. Opuitn. Agron. [Jour. Expt. Landw.~\, 5 (1904), No. 1, pp. 

 121-123). — The author critically reviews various methods which have been proposed 

 and describes the following modification of the Fadyeyev-Williams method: Four 

 grams of soil passing through a sieve with 1 mm. holes is made to the consistency of 

 a thin gruel, triturated with the finger 2 to 5 minutes, and transferred to a flask of 

 125 cc. capacity, in which it is boiled for 1 hour. For the separation of the particles 

 0.25 to 1 mm. in size a small sieve placed in a porcelain dish of \\ liters capacity is 

 used. 



For the separation of the particles less than 0.01 mm. the turbid liquid is trans- 

 ferred by means of a siphon to a small porcelain dish, from the latter after 100 sec- 

 onds into a graduated beaker (100 cc. capacity, 8 cm. high), and thence into large 

 (\\ to 2 liters) beakers — process of double sedimentation. Toward the end the soil 

 is triturated with the finger in both dishes in order to bring about complete separa- 

 tion. The separation of the particles 0.01 to 0.05 mm. is effected in a tall cylinder 

 beaker (into which the soil was transferred from the small beaker and the small 

 porcelain dish in order to test the completeness of the last separation) from which 

 the turbid liquid with the suspended particles is transferred every 30 seconds into a 

 large beaker. The same treatment is given to the residue in the large porcelain dish. 



The remainder of the soil after this separation represents the particles 0.05 to 

 0.25 mm. in diameter. In the further division of the 0.01 mm. particles the author, 

 besides the boiling during 24 hours usually practiced in the separation of the 0.001 nun. 

 particles, boils the sediment in a small Erlenmeyer flask and pours the turbid liquid 

 into 3 to 5 small beakers to the height of 4 cm., from which, after 4 hours and 48 

 minutes, 2 cm. of the liquid is decanted, which hastens the separation. The separa- 

 tion of the particles 0.001 to 0.005 mm. is made in the same kind of beaker. — 



P. FIREMAN. 



Action of hydrochloric acid on the soil under different conditions, S. Brush- 

 linski (Zhur. Opuitn. Agron. [lour. Expt. Landw.~\, 4 (1903), No. 5, pp. 517-524). — 

 The author compared the action of hydrochloric acid on soils under varying condi- 

 tions of time of treatment, concentration of acid, and excess of acid. On the basis 

 of his own experiments and those of other investigators he concludes that the influ- 

 ence of the length of time, within moderate limits, is not marked, that the effect of 

 concentration of the acid is not considerable as long as the variations in this respect 

 are not extreme, and that only the relative quantity of the acid and soil is decisive 

 in respect to the amount of soil going into solution. — p. fireman. 



