615 



per pound for nitrogen, 7 cents for phosphoric acid, and 4.5 cents for 

 potassium oxide, a valuation used by the station on a former occasion, 

 the vahie of the fertilizing materials from the grain would be $24.35.] 



New York Cornell Station, Bulletin No. 37, December, 1891 (pp. 49). 



Work of chemical division, H. Snyder, B. S. (pp. 357-365). 



Bthrini tuition o//at,s in fodders by direct weighing of the ether extract 

 and by loan of iveig/it of the substance (])p. 357-360). — A comparison was 

 made on twelve different feeding stuffs of the percentage of fat found 

 by weighing the dried etlier extract (as is usually done), and by the 

 loss in weight of the feeding stuff by extraction with ether. The tests 

 were made with the ai)paratus described by G. C. Caldwell, Ph. B., in 

 Bulletin No. 12 of the station (see Experiment Station Eecord, vol. i, p. 

 278), for drying substances in hydrogen and for the extraction of 

 fat, which "serves the double purpose of glass-stoppered weighing 

 tubes and as drying tubes." 



The total average by weighing the fat was 0.006 per cent higher than by the h).s3 

 of weight, a difterence which is insignificant. 



The tubes are more convenient for drying tlian Hasks, and no additional or 

 expensive drying apparatus is required asfor the liasks. The drying of the tnbes al'ter 

 the extraction can be done much more quickly and efiliciently than drying the flasks 

 for the gas passes through the substance rather than over its surface, therebv 

 requiring less hydrogen. More than this, the results show that the use of hydrogen 

 ill this second drying can be dispensed with. 



Ou the whole, therefore, it is more economical as to time, apparatus, and hvdro'Ten 

 to determine the fats by loss of weight of tbe .substance, while there is no loss in 

 accuracy. 



Determination of albuminoid nitrogen (pp. 360-362). — In determining 

 albuminoid nitrogen by means of copper hydroxide and the Kjeldahl 

 method, the author found it necessary to add more potassium sulphide 

 than was called for by the official recommendations for 1890. In com- 

 parative tests on silage, in which 20 and 50 c.c. of potassium sulphide 

 were used, results nearly 0.1 per cent higher were secured with 50 tliuii 

 with 20 c. c. 



A difference of 0.1 per cent when multiplied by the protein factor would make a 

 difference of over 0.6 per cent of protein, which is too great to be overlooked. 



Some change must therefore be made in combining Stutzer's and Kjeldahl's meth- 

 ods.* The following proportions of substance and solutions have given me satistiic- 

 tory results: Take 0.7 gr. of substance instead of Igr., a quantity of copper hydroxide 

 and glycerin solution equivalent to 0.5 to 0.6 gr. of the Jiydroxide instead of 0.7 to 

 0.8, and finally 30 c. c. of potassium sulphide instead of 20 c. c. 



Dryaig aampJes of fresh manurefi (inp. 262, 263). Tlie drying can be carried on by 

 artificial heat, without loss of ammonia, in the following simple manner: Tlie 

 sampling bottle in which the manure is received is provided with a two-lioie 

 rubber stopper. Through one of tJiese holes a glass tube with six or eight holes 

 blown out through its walls is carried to the bottom of the bottle ; another tube 



* The present official method calls for "sufficient potassium sulphide solutiou to 

 completely precipitate all copper and mercury." 



