EXPERIMENT STATION BULLETINS. 401 



forty-eight hours on the sand bath with 25 parts by weight of 25 per 

 cent sulfuric acid in a flask fitted with a reflux condenser. While 

 still hot, the dark brown liquid was filtered, with suction, through a 

 Buchner funnel having a solid unglazed, porcelain bottom. The in- 

 soluble material was returned to the flask, heated with a fresh supply 

 of water and again filtered. This was repeated several times until the 

 wash water came through colorless. The filtrate and washings were 

 made alkaline with slaked lime and the precipitate of calcium sulfate 

 allowed to settle. The supernatant liquid was then poured through a 

 filter and the precipitate washed several times by decantation with hot 

 water. The liquid thus obtained was concentrated to about one-third 

 its volume and filtered from a small precipitate of calcium sulfate and 

 humus. Barium hydroxide was added to the filtrate in slight excess and 

 the precipitate of barium sulfate filtered off and thoroughly washed.^ 

 The hydroxides of barium and calcium remaining in solution were then 

 removed b}- passing carbon dioxide into the hot solution and filtering 

 off the precipitated carbonates by suction. By this process all of the 

 sulfuric acid can be removed together with the reagents used for its 

 removal, leaving only the products of the extraction in solution. Most 

 of the brown, amorphous, humus material is held back so that at the end 

 one has, at most, only a light brown solution. The amount of mineral 

 matter was very small and was precipitated as a light-colored, sandy 

 powder, during the concentration, before the organic matter came down. 

 After removing this small precipitate, the solution was made slightly 

 acid and a solution of phosphotungstic acid sloAvly added until it failed 

 to cause a further precipitation. The precipitate thus formed was light 

 gray and flocculent. It was filtered off and washed with hot water. 

 Both the filtrate and precipitate were then boiled with an excess of 

 barium hydroxide and filtered, after which the excess of barium hydrox- 

 ide was removed with carbon dioxide and the solutions concentrated. 

 The one resulting from the decomposition of the phosphotungstic acid 

 yielded only a brown viscous mass, which failed to crystallize. 



A light yellow scale formed on the surface of the other solution and 

 as the concentration was continued, waxy knobs and clusters were 

 formed on the sides of the dish. This material was separated from the 

 rather oily mother liquor, dissolved in water and, after boiling with 

 animal charcoal, recrystallized. After several recrystallizations it was 

 obtained colorless, separating in waxy knobs and clusters when allowed 

 to crystallize slowly or as a white crust when the mother liquor was 

 more concentrated. It was further purified by precipitation from a 

 concentrated aqueous solution with absolute alcohol. After being puri- 

 fied in this way it crystallized in white flakes. It was readily soluble in 

 water but almost insoluble in absolute alcohol and most organic solvents. 

 The aqueous solution was neutral to litmus. When the solid substance 

 was heated in a capillary tube it softened at 230° and decomposed at 

 265-269°, giving a white crystalline sublimate in the upper part of the 

 tube. The mother substance analyzed as follows: 



0.0696 g. subst. gave 6.7 cc. N at 25° and 748 mm. 



Calculated for CcHiaO^N: N, 10.68. Found, 10.56 per cent. 



'Where only small quantities of peat and sulfuric acid are used, it is, of course, better to precipitate 

 all of the acid with barium liydroxide. Wlien larse quantities of acid are being used, however, it is 

 more economical to precipitate the bulk of it with lime and use the barium only for that wmch remains 

 in solution as calcium sulfate. 



51 



