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bleachiii» or otherwise working up damaged flour various salts are used. 

 Of these the most common, and that against which the greatest outcry 

 has been made, is alum. This salt is almost invariably used, notwith- 

 standing a very stringent law specially framed to prevent its use, but so 

 easily is this law avoided that in many parts bakers refuse to 

 work unless their accustomed bag of stuff is in its wonted place in the 

 bakery, and the master has no difficulty in granting their demand, 

 unless perchance his own conscience interfere. 



The etfect of this addition is to increase the whiteness of the bread, 

 to enhance its hygroscopic properties, so that the weight is augmented 

 by retained moisture. It imparts a sweetness to damaged flour 

 not otherwise possessed, and last not least, it greatly facilitates the 

 separation of the loaves when baked, a desideratum of no mean import- 

 ance to the journeyman baker. 



The action thus exerted by the alum is undoubtedly of a chemical 

 nature, and one, we imagine, closely allied to that which takes place 

 when alum is used as a mordant in the process of dying. The im- 

 portant position alum occupies in this process, to precipitate and fix the 

 coloiir, is too well known to require comment hei'e ; sufiQce it to say 

 that the alum, consisting of a double sulphate of alumina and potass, 

 suffers decomposition, the earthy alumina being precipitated in combina- 

 tion \vith the colouring matter. lu the process of baking bread con- 

 taining alum, we conceive a like decomposition takes place, the alumina 

 combining with the colouring and other nitrogenous matter of the 

 flour, while the sulphate of potass is liberated as a free salt, so that 

 instead of the bread containing an astringent and irritant double salt, 

 it simply contains the elements of that salt in a new and perfectly 

 innocuous combination. 



This is by no means a novel theory; but it has not, we think, received 

 that attention which it deserves. For the purpose of determining its 

 validity we have submitted various samples of bread to analysis, known 

 to have been made with the addition of alum, but in no case were we 

 able to isolate, in crystals or otherwise, a single trace of the astringent 

 double salt of potass-alum, and we feel perfectly certain that where 

 the admixture of alum and process of baking have been dexterously 

 conducted, it is impossible to obtain a single grain of alum in its 

 original state. We have found alumina in varying proportions in the 

 ash of aU the breads we have analysed. 



If this theory be correct, and our experience tends to establish it, 

 then we think the great objection to the use of alum is removed, for it 

 is so entirely decomposed as to become perfectly haiToless ; and seeing 

 that its addition renders inferior flour perfectly wholesome and equally 



