No. 7.] DONALD — BAKING POWDERS. 411 



renders it light and porous. Before proceeding further it Tvill 

 be necessary to define an ideal baking powder wherewith we 

 may compare powders that are offered for sale throughout the 

 land. Our ideal powder then is a mixture of one part soda 

 bicarb, with as nearly as may be, two parts cream of tartar. 

 When moistened these substances acting upon each other give off" 

 about 16-5 per cent, of carbonic dioxide, tartrates of potassium and 

 sodium being formed, none of which are iujurious to the human 

 system. 



And just here I miy be permitted to add that if our Govern- 

 ment intend the law concerning adulteration of food to be any 

 more than a de;id letter, in so far as this substtnce is concerned 

 it will be necessary for it to define a pure article, which should 

 be done by stating the minimum amount of carbonic acid that 

 the powders shall produce and the acid substances which may or 

 may not be used, for as matters stand at present any one may 

 call his powder pure, for so it miy be according to his formula 

 and his idea of pure and impure baking powders. 



It has fallen to my lot to examine a large number of baking 

 powders, nearly every powder manufactured to any extent in 

 Canada, and also many from the United States. Nearly all that 

 I have examined may be included in three classes : 



The first class contained those powders which come sufficiently 

 near to our theoretical one to be called commercially pure. 



One of these contained besides soda and cream of tartar 10-61 

 per cent, of flour, and produced 15--1 per cent, of carbonic dioxide. 



A second contained, in addition to the essential ingredients, 

 flour 9-8 per cent, and lime nearly 2 per cent., and gave off 15'5 

 per cent, of carbonic dioxide. 



Another contained, in addition to soda and cream of tartar, flour 

 3'2 per cent, and lime 2*78 per cent. 



The only points wherein the members of this group depart 

 from our type is that they all contain flour, from 3 to 10 per 

 cent., and that two of them have a small quantity of lime. 



Now, whilst flour is certainly not essential to a baking powder 

 as such, it is a necessary ingredient of a powder which is to fully 

 retain its properties for any length of time. When mixed with 

 the soda bicarb, and cream of tartar it to a certain extent 

 keeps the pirtlcles of the two substances apart ; did they lie in 

 immediate contact a certain amount of the carbonic acid would 

 be dissipated and the powder lose strength. I cannot say with 



