BAKING POWDERS. 611 



This and the preceding sample are made by the same firm, and are 

 very similar in composition. 



5515. Patapsco Baking- Powder. 

 [Made by Smith, Han way & Co., Baltimore, Md. Put up in glasses.] 



Available carbonic acid - per cent.. 7. 58 



Cubic inches per ounce of powder at 212'F 91. 1 



PERCENTAGE COMPOSITION. 



Total carbonic acid, COa 9. 18 



Sodium oxide, NaaO 9.83 



Aluminium oxide, A1 8 O 3 4.55 



Calcium oxide, CaO 2.77 



Phosphoric acid,PaO 6 1.44 



Sulphuric acid, SO 3 - 13.01 



Ammonia, NH 3 .91 



Starch 41.24 



Water of combination and association by difference 17. 07 



100. 00 



PROBABLE PERCENTAGE COMBINATION. 



Sodium bicarbonate, NaHCO 3 17. 52 



(Residual sodium oxide Na 2 O) 3.36 



Ammonia alum, anhydrous : 



A1 2 (SO 4 ) 3 15.15 



(NH 4 ) 2 SO 4 3.53 



18.68 



Calcium sulphate, CaSO< .46 



Acid phosphate of lime, anhydrous: 



CaO 2.53 



P 2 O 5 1.44 



4.02 



Starch 41.24 



Water of association (phosphate) and crystallization (alum) 14. 72 



100.00 



This and the three samples following all have the same brand, but 

 were put up in different shape, No. 5515 being contained in glass bot- 

 tles, No. 5516 in tin cans, and No. 5517 being sold in bulk. No. 5519 is 

 another brand made by the same firm. Of these, Nos. 5515 and 5517 

 give very similar results on analysis, while in Nos. 5516 and 5519 the 

 numbers agree closely with one another, though quite different from the 

 other two samples. In Nos. 5515 and 5517 the acid phosphate of lime 

 is given simply as the sum of the per cents, of CaO and P 2 O 5 found. 

 There is probably considerable calcium sulphate in these samples, but 

 if the sulphuric acid is combined with all the alum there is not enough 

 left for combination with the lime. 



