AGRICULTURAL CHEMISTRY AGROTECHNY. 15 



round colonies are formed which also will form black spores. The second 

 culture, A. alho-roseus, on filter paper forms white, chalklike flakes, but later 

 red pigment is produced which colors both the filter pai>er and the nutrient 

 solution. On ammonium sulphate dextrose agar and on bouillon dextrose 

 agar white aerial spores are produced, but on bouillon agar no aerial spores 

 are obtained. The aerial spores of A. mclanocyclus resemble cocci while those 

 of A. albo-roseus are oval or bacilli-like. Although both of the organisms de- 

 compose cellulose, A. melanocyclufi is stronger in this resiiect. Reducing sugars 

 were not found in the culture medium. 



A new and simple titrimetric method for determining thiosulphate in 

 the presence of sulphites, J. Bounau {Kisdrlet. Kijzlcin., 16 {1913), No. Jf, 

 pp. 55^-561). — The method, which is used for Hme-sulpiiur wash, depends upon 

 the fact that silver thiosulphate will become decomposed by the interaction 

 of water and sulphuric acid results. By simply titrating the sulphur content, 

 the amount of thiosulphate taking part in the reaction can be estimated. The 

 method can also be used for determining the titer of a sodium thiosulphate 

 solution even though large amounts of sulphites are present. 



By the iodometric method suli)hiies can be estimated when thiosulphates are 

 present, providing the amount of thiosulphate is known. This can easily be 

 determined by the author's method. The method has the advantage over Gut- 

 mann's method in so far that the presence of chlorids does not interfere with 

 the results. 



The detection and approximate determination of traces of thiosulphate in 

 sulphites, J. BoDNAR {Kis6rlet. Kozlvin., 16 {1913), No. 4> PP- 562-566). — If 

 silver nitrate is added to a sulphite solution (sodium sulphite), silver sul- 

 phite is deposited, which when exi>osed to the air will retain its color for a 

 long time. Silver thiosulphate, on the other hand, loses its whiteness rapidly 

 and turns lemon yellow, orange yellow, dark brown, and finally black. Conse- 

 quently if silver nitrate is added to a sulphite solution which contains 

 thiosulphate, a white precipitate is not obtained, but according to the amount 

 of thiosulphate present a light yellow up to a black precipitate results. 



The above reaction will detect as little as 0.3 cc. of fiftieth-normal sodium 

 thiosulphate in 5 cc. of a 10 per cent sodium sulphite solution, corresponding 

 to 0.09 per cent of sodium thiosulphate. As the intensity of the color is pro- 

 portional to the amount of thiosulphate present, the method may serve as an 

 approximate one for estimating the amount of thiosulphate in sodium sulphite. 



The reactions of Reynold, Koninck, Musset, Arnold, and Gutmann were 

 found less sensitive than the one proix)sed above. 



Estimating the fineness and the chemical examination of flowers of sul- 

 phur and ground sulphur used for combating plant diseases, T. S. Hofman 

 {Verslag. Landhouwk. Onderzoek. RijksJanddouwproefstat. [Netherlands], No. 

 H {1913), pp. 1-8). — In Holland sulphur is used chiefly for dusting vines and 

 rose plants for combating mildew diseases. The fineness of sulphur detei-miues 

 to quite an extent its adhesive power, and for estimating the fineness a modifi- 

 cation of Chancel's method is employed. According to the original method 5 

 gm. of sulphur is shaken with ether in a calibrated tube termed a " sulphurime- 

 ter," which is described in detail. The finer the sample of sulphur, the greater 

 is the space which it occupies. 



In order to reduce the error in these experimental tests 40 instead of 5 gm. 

 of sulphur was taken, and instead of ether alcohol was used. The results ob- 

 tained by Chancel's method and the modified method are reported. 



For judging sulphur the following shoifld be noted: (1) the color and the 

 appearance; (2) the texture as noted by the tips of the fingers; (3) the ap- 

 pearance under the microscope; (4) the solubility in carbon bisulphid; (5) its 



