12G § 88. BASES AND ACIDS WITH REAGEI^S. 



(Sp. Gr. = 0.72), evaporating tlie etherial solution of fat to 

 dryness, and weighing the residue. 



Several portions of ether must be used, and the extrac- 

 tion is best conducted in a flask i^^ovided with tubes like 

 a washing-bottle, and which is connected with the lower 

 end of a Liebig's condenser (§ 36). 



The extraction may not be considered as ended until a 

 drop of the last filtrate leaves no residue when evaporat- 

 ed on a watch-glass. The solutions, if not perfectly clear 

 as they came from the filtering flask, should be filtered 

 through j)aper. The chlorophyll in the green parts of 

 plants goes into solution with the fat, but it may be re- 

 moved by filtration thi-ough bone-black. 



The clear etherial extracts may be collected in a gradu- 

 ated cylinder, and the fat determined in an aliquot part of 

 the well-mixed liquid by evaporation to dryness, drying 

 the residue at 100° C, and weighing. 



ALCOHOL. CsTIeO. 46. 



88. Alcohol is miscible with water in all proportions. 



Quantitative estimation. — This is efiected by distilling 

 the alcohol ofl", and estimating it in the distillate by the 

 specific gravity. 



a. To 10 c.c. of the solution to be examined, which 

 must contain no free volatile acid, as acetic, for example, 

 add its volume of water, and subject the Avhole to distill- 

 ation in a small flask connected with a small Liebig's 

 condenser. Collect the distillate in a specific-gravity bot- 

 tle with a mark on it, indicating a capacity of 10 c.c. 

 When somewhat less ^ than half the liquid has been dis- 

 tilled over, remove the specific-gravity bottle frora the 

 tube of the condenser, bring the temperature of the dis- 

 tillate to 15° C.jfiU up to the mark with water, and ^\'eigh. 

 Knowing the weight of 10 c.c. of Avater at this tempera- 



