BAKING POWDERS. 593 



are usually enough). Filter, wash with dilute ammonia, ignite intensely 

 for ten minutes, and weigh. 



ESTIMATION OF TARTARIC ACID. 



The method used in this estimation was that known as the " Golden- 

 berg Geromont," which is described in full in Chemiker Zcitung, 12. 1888, 

 390. This and other methods for the estimation of tartaric acid in 

 crude argol and other raw materials were lately submitted to a critical 

 comparison in the tartrate factory at Nienburg; 1 the Goldenberg- 

 Geromont method avoided the principal sources of error and is recom- 

 mended as the best and most easy of execution. 



The procedure as modified for application to a tartrate baking-pow- 

 der is as follows: 



Weigh out 5 grams, wash into a 500-cubic centimeter flask with about 

 100 cubic centimeters of water ; add 15 cubic centimeters of strong hydro- 

 chloric acid ; make up to mark and allow the starch to settle. Filter, 

 measure out 50 cubic centimeters of the clear filtrate ; add to it 10 cubic 

 centimeters of a solution of carbonate of potash containing 300 grams 

 K 2 UO 3 to the liter and boil half an hour; filter into a porcelain dish and 

 evaporate filtrate and washings to a bulk of about 10 cubic centimeters. 

 Add gradually with constant stirring 4 cubic centimeters glacial acetic 

 acid, and then 100 cubic centimeters of 95 per cent, alcohol, stirring the 

 liquid until the precipitate floating in it assumes a crystalline appear- 

 ance. After it has stood long enough for this precipitate to form and 

 settle, best for several hours, decant through a small filter, add alcohol 

 to the precipitate, bring it on the filter, wash out the dish and finally 

 the filter carefully, with alcohol, until it is entirely free from acetic acrd. 

 Transfer filter and precipitate to a beaker, add water and boil, washing 

 out the dish also with boiling water if any of the precipitate adheres 

 to it. The resulting solution is titrated with decinormal alkali solution, 

 using phenol-phthalein as indicator; 1 cubic centimeter decinormal 

 alkali corresponds to .0188 grams of potassium bitartrate, or .0150 grams 

 of tartaric acid. 



ESTIMATION OF ALKALIES. 



The estimation of the soda and potash in the powders was carried 

 out by separating them as chlorides, determining the potash as potas- 

 sium platiuic chloride ami calculating the difference as sodium chloride. 

 The detailed procedure was similar to that used by the Association of 

 Official Agricultural Chemists for determining potash in fertilizers, as 

 follows : 



Weigh out 5 grams into a platinum dish and incinerate in a muffle 

 at a low heat. The charred mass is well rubbed up in a mortar, then 

 boiled 15 minutes with about 200 cubic centimeters of water to which 



1 Chemiker Zeitnng 13, 1889, 160. 



