BAKING POWDERS. 



585 



The wheat powder was put up in tin boxes, without starch or other filling. One 

 sample was in excellent order, the other much caked. 



III. Alum and phosphate poivdera. This class embraces powders showing ammonia, 

 soluble sulphates, alumina, and phosphates, when tested as already described. 



A few showed potash reactions, and in some there was evidence of tartaric acid or 

 some other substance reducing silver abundantly from ammoniacal solutions. In such 

 cases, of course, potash alum and bitartrate of ammonium may have been present, 

 or the reactions may have been caused by cream of tartar, or by free tartaric acid. 

 The possible combinations are very numerous, and the analysis, however complete, 

 will not always indicate the exact combination. Inasmuch as some of these powders 

 showed considerable alumina in the simple water solution, a more detailed examina- 

 tion of them is recommended, for the reasons already given. The actual presence of 

 acid phosphate of lime, or of any other acid phosphate, was not proven, but all con- 

 tained some phosphate, and have therefore been classed as indicated, although prob- 

 ably in every case they were made with acid phosphate of lime. 



As already mentioned, the low grade of several is, perhaps, from deterioration, due 

 to the presence of the acid phosphate in packages not sufficiently air-tight. Acid phos- 

 phate will not keep well when mixed with bicarbonate of soda, except in well-corked 

 bottles. Tin cases are not tight enough. 



Many of these powders contained sulphate of lime, chemically equivalent to terra 

 alba. This was, perhaps, in no case added as an adulterant, but was a part of the 

 acid phosphate of lime used ; the latter not having been separated from the sulphate 

 of lime formed in its manufacture. The presence of this sulphate of lime must be 

 regarded as objectionable. None of these powders are as strong as they might be 

 made, and most of them are very deficient in strength. Apart from questions of 

 healthfulness, there can be uo economy in buying some of these powders. 



IV. Alum powders. Here are classed the powders showing the same reactions as 

 the preceding class, but free from phosphates. All appeared to be ammonia alum 

 powders, but reactions for potash and tartaric acid were not wanting among them. 

 Only one of them begins to come up to the strength which a " straight " burnt am- 

 monia alum powder might have. 



V. Unclassed powders. The composition of these will be indicated under the special 

 remarks. 



I. Cream of tartar powders. 



