1826.] on the Art of Baking Bread. 267 



of each of the doughs were set aside, according to the custo- 

 mary practice, for about six hours. Before the half of this 

 period had elapsed, the dough prepared with yeast was in a 

 state of strong fermentation, and had swelled out to fully thrice 

 its original volume. On the contrary, the two other pieces of 

 dough, throughout the whole course of the six hours, never 

 exhibited the slightest appearances, either of fermentation or of 

 expansion. Portions of each were now again detached ; and 

 after they had been kneaded and set aside for about half an 

 hour, in a warm situation, with a view to permit a fresh accumu- 

 lation of carbonic acid gas, they were then baked, as before. 

 The bread formed out of the dough which had been fermented 

 in the regular manner by means of yeast,, was light and spongy, 

 and possessed all the characters of ordinary bread ; but that 

 which was the product of the doughs prepared with a saturated 

 aqueous solution of carbonic acid gas, was still as dense, tough, 

 and unvesicular, as in the first trials that had been made, imme- 

 diately after the intermixture of the flour with the water. There 

 still remained a portion of each of the three original masses ; 

 these, after having been again abandoned to themselves in a 

 warm situation, as before, for about twelve hours, were carefully 

 examined ; bat even at the expiration of this period, those 

 which had been prepared merely with flour and a solution of 

 carbonic acid gas in water did not appear to have undergone 

 any fermentation or expansion. The same series of experiments 

 was afterwards repeated with no other variation than this, that 

 brisk soda-water was substituted in the room of the original 

 solution of carbonic acid gas. The results were identical in 

 every respect with those which have been just detailed : it 

 would be unnecessary, therefore, to enter into a more particular 

 account of them. 



The conclusions from all these experiments are, therefore, 

 wholly inconsistent with the opinions of Edlin, and those attri- 

 buted to Henry, and seem to be a convincing proof, both that 

 carbonic acid gas is incapable of exciting the panary fermenta- 

 tion, and that it is impracticable, by the mere employment of a 

 saturated aqueous solution of carbonic acid gas, to cause the 

 dough to expand in the process of baking into a light, spongy 

 bread. 



The experiments made on the decomposition of an alkaline 

 carbonate within the substance of the dough, afforded results 

 rather more favourable to the views of Messrs. Edlin and Henry, 

 although they at the same time proved decisively that this pro- 

 cess by no means possesses the efficacy which is ascribed to it 

 in the statements of these chemists. The carbonates which 

 were selected for the purpose of these assays, were the sesqui- 

 carbonate of soda, and the common carbonate of magnesia, and 

 due care was always taken to employ the; acid and alkali in 



