AGRICULTUEAL CHEMISTRY AGROTECHNY. 13 



sary. The filters containins tlie organic portions of the fertilizer are dried in 

 an air bath, cooled, weighed, and preserved for microscopical and chemical 

 analyses. 



The above procedure has been subjected to extensive use on many commer- 

 cial fertilizer and crude nitrogenous stock samples. It was found that the fol- 

 lowing materials float on carbon tetrachlorid : Dried blood, fish, tankage, hoof 

 meal, horn meal, leather, kanona tankage, morocco clippings, azotin, cotton- 

 seed meal, castor meal, castor pomace, beet refuse compound, nitrogenous 

 manure, casein, peat, garbage tankage, tartar pomace, mowrah meal, rape meal, 

 soy-bean meal, wheat gluten, tobacco stems, fillerine (partly), and cinders (cer- 

 tain types). Ground bone, nitrate of lime, cyauamid, grape pomace, aluminum 

 nitrid, nitrate of soda, sulphate of ammonia, acid phosphate, rock phosphate, 

 basic slag, dissolved bone black, animal charcoal, muriate and sulphate of pot- 

 ash, and kainit sink in carbon tetrachlorid. 



A table is given showing the results obtained by the chemical analysis of the 

 floats, including the determination of water insoluble nitrogen by the alkaline 

 permanganate method (E. S. R., 23, p. 705) and also the finding obtained by 

 visual inspections. The results show large variations in the nitrogen content 

 of the mixtures which contribute to furnish the organic nitrogen found In com- 

 mercial fertilizers. The water insoluble nitrogen indicates similar ranges. 



The inorganic portions of the samples were also tested as regards their insol- 

 uble nitrogen content and its activity. The activity noted compared favorably 

 with that shown by the organic (float) portion. 



A classification for organic nitrogen activity as determined by the alkaline 

 permanganate method is presented. The method may be used for other pur- 

 poses also. 



Comparison of a few methods for total phosphoric acid in superphosphate, 

 C. A. Peteks {Jour. Indus, and Engin. Cheni., 7 {1915), No. 1, pp. 39, 40). — 

 These data were taken from a thesis presented at the Massachusetts Agricultural 

 College by A. G. Weigel, and consist of the results of a comparative study of 

 a superphosphate homemade from ground rock. The results confirmed previous 

 knowledge, indicating that " the official gravimetric method of determining total 

 phosphoric acid gives high results when phosphoric acid is determined in super- 

 phosphate without evaporation of the solution to dryness on a steam bath to 

 remove silica. Several methods other than the official gravimetric give equally 

 good results in half the time." 



The determination of creatin in muscle, L. Baumann (Jour. Biol. Chem., 17 

 {1914), ^^0. 1, pp. 15-17). — Many of the methods proposed in the literature for 

 determining the creatin in flesh and blood are tedious and time-consuming. A 

 method which follows gives results that are within the limits of experimental 

 error. 



" Fifty gm. of hashed muscle is weighed into a round bottom, short-necked 

 Jena flask ; to this 125 cc. of 5 times normal sulphuric acid and a few chips of 

 unglazed porcelain are added and the whole boiled for three hours under a 

 reflux condenser. At the end of this time the muscle is disintegrated. The 

 solution is now filtered quantitatively through a 15 cm. filter paper into a 250 

 cc. volumetric flask (the volume of the sulphuric acid and the dilution being 

 proportional to the weight of muscle used for analysis), the residue (less than 

 2 gm. of dry material) is washed thoroughly with distilled water, the fluid is 

 cooled, and the flask filled to the mark. 



" Twenty cc. of the claret-colored extract is pipetted_ into a small porcelain 

 disk (8.5 cm. in diameter) and 18 cc. of 10 per cent sodium hydrate is added 

 while stirring. The partially neutralized fluid is then evaporated on the water 



