AGKICULTURAL CHEMISTRY — AGROTECHNY. 113 



Ammonium oleate conld be obtained by passing dry ammonia into an ethereal 

 solution of oleic acid. Tbis salt with water forms a colloidal, gelatinous liquid, 

 wliich can not be filtered through paper, and which froths when shaken with a 

 large amount of water. It was much more soluble in alcohol than the stearate 

 or palmitate. The author utilizes this fact for separating solid from liquid 

 fatty acids as '* at a little above 0° C, 100 cc. of absolute alcohol, rendered am- 

 moniacal, will dissolve 31 gm. of ammonium oleate, but only 0.1 gm. of am- 

 monium stearate and 0.5 gm. of ammonium palmitate. 



" The proposed method is as follows : The mixed fatty acids are dissolved in 

 a small quantity of warm ether, a current of ammonia gas is passed through 

 the solution, and the latter is cooled to the ordmary temperature. After ex- 

 pelling the ether, the residue Is agitated with about four times its volume of 

 ammoniacal alcohol cooled to 0°C., and after breaking up any clots and cooling 

 in melting ice, filtered with the aid of the pump, and the precipitate is washed 

 with a small quantity of cooled alcohol. Ftom the filtrate and precipitate the 

 liquid and solid fatty acids respectively are separated in the usual manner. 

 The method while not giving entirely exact results, is stated to be sufficiently 

 accurate for technical purposes, and the author has used it for determining the 

 liquid and solid fatty acids of tallow, lard, sesame oil, etc." 



The saponification methods for edible fats, E. Poppe (Separate from Vers- 

 lag. en Meded. K. Vlaam. Acad. Taal en Letterk., 1910, pp. 58). — This is a 

 detailed description and discussion of practically all the saponification methods 

 in existence. It is accompanied by analytical results of the author, etc. 



Analyses of fats and tlie chemistry of fats, W. Fahkion (Ztschr. Angew. 

 Chem., 24 {1911), A"o. 6, pp. 2.}i-254).— This is a retrospect of the more im- 

 portant progress made in the chemistry of fats for the year 1910. 



The estimation of essential oils, C. D. Howard {Jour. Indus, and Engin. 

 Chem., 3 (1911), No. 4, p. 252).— The author points out that while the method 

 previously proposed by him (E. S. R., 20, p. 113) will sometimes yield inac- 

 curate results with mixtures containing certain essential oils, ia the case of 

 such oils as orange, lemon, wintergreen. and peppermint it is of considerable 

 value. The procedure has been modified and is as follows : 



" Transfer 20 cc. of the extract to a 4-oz. separatory funnel ; in the case of 

 preparations containing more than 5 per cent of oil, take but 10 cc. Add 50 

 cc. of water and (except in the case of oils of the type of cinnamon and clove) 

 2 drops of strong hydrochloric acid. Shake out with 3 portions of ether, using 

 15 CO., 10 cc, and 5 cc. After each extraction except the last, the ether solution 

 may be run out into a small flask, which is kept stoppered if a series of determi- 

 nations is being run simultaneously. The combined ether extracts are washed 

 once with 10 cc. of ether-saturated water for removal of the bulk of the alcohol, 

 then cautiously transferred to a 10 per cent milk bottle, rinsing the flask and 

 tip of the funnel with an additional 2 or 3 cc. of ether. Attach a bulb tube to 

 the stem of the bottle and connect with a filter pump, immerse the bottle in 

 nearly boiling water, start the pump and shake with a gentle rotary motion at 

 first. When all danger of spirting has passed, shake violently, and toward the 

 last immerse in boiling water for a few seconds, or until the application of a 

 match flame demonstrates the complete elimination of the ether. The removal 

 of most of the latter should require not more than 2 or 3 minutes. Finally add 

 cold water and centrifuge. In the case of oils heavier than water, salt solution 

 must be used as the floating agent, except with wintergreen, for which cold 

 sulphuric acid (1:2) may be safely and most com-eniently used." 

 See also a previous note by Hortvet and West (E. S. K., 21, p. 108). 



