33 



more cc of strong alcohol on the water bath. If the soap is very hard it 

 inav he as well to leave it in contact with the alcohol overnight, so as to 

 soften it. Evaporate off the alcohol and dry in the oven at llo C., 

 either to constant weight or to the point where it only gains or loses a 

 little during one-half hour extra drying. 



T<tt<il faff;/ mutter. Five to 10 grams of the soap is dissolved in hot 

 water i n a beaker by means of gentle heat and constant stirring. When 

 the liquid tinally begins to boil, a few drops of methyl orange are 

 added and dilute hydrochloric acid until the indicator shows an acid 

 reaction. Continue the boiling and stirring until all fatty matter has 

 collected in drops. Add about 5 grams of dry beeswax, accurately 

 weighed on a weighed watch glass. Boil again till the fat collects 

 on the top as a clear layer free of specks. Rinse off the rod and boil 

 till the fat has again collected. Allow the contents of the beaker to 

 cool until the fatty layer has entirely solidified. Remove this layer 

 by means of a platinum spatula, wash with cold water, dry between 

 filter papers, and transfer to the weighed watch glass previously 

 spoken of . Gather together all particles of fat left behind by means 

 of the platinum spatula, and when this is not possible by means of 

 small weighed pieces of filter paper, add to the watch glass and con- 

 tents, dry in a desiccator overnight, and weigh. The total weight 

 thus obtained, minus the combined weights of the watch glass, bees- 

 wax, and pieces of filter paper, gives the weight of the total fatty 

 matter. In the absence of resin, neutral fat, and unsaponifiable 

 matter, all of this fatty matter is reported as fatty acids, but if any of 

 the other three are present they are subtracted and the remainder 

 reported as fatty acids, which multiplied by 0.965 gives fatty acid 

 anhydrid. 



Tot<il alkali A. weighed quantity of the soap is decomposed by 

 hydrochloric acid and the water is filtered off from the fat, which is 

 washed. Both potassium and sodium in the filtrate are first deter- 

 mined as the mixed chlorids in the ordinary manner, and the potassium 

 then determined by means of platinum chlorid solution. 



Free caustic alkali. -Dissolve 30 grams of the soap in strong or abso- 

 lute alcohol. Filter rapidly by means of a hot-water funnel into a 

 narrow-necked flask. Wash the filter with alcohol till clean. The 

 filtrate is now titrated with N 10 hydrochloric acids, using phenol 

 phthalein as indicator. In the case of all whale-oil soaps examined, an 

 acid reaction was obtained at this point denoting free fatty acids. 



Calcium oxid. This was found to be present in one sample of soap 

 and was determined by first acidifying a weighed quantity of soap in 

 water solution with hydrochloric acid, just as in the determination of 



1301 No. 6802 3 



