and on the Means of improving the Flour. 177 



the new flour in the act qf drying appears to lose nothing but 

 water, and after being well dried it still makes bread of indiffe- 

 rent quality, the process of drying can only be regarded as a 

 useful auxiliarv, and by no means supersedes the application of 

 other substances as correctives. 1 have said a moderate warmth, 

 long continued, seems to improve the flour more than a higher 

 temperature. This difference may probably arise from various 

 considerations. As sugar appears to be injurious to flour, and 

 the new flour contains an excess of saccharine matter, and is in 

 a comparatively moist state ; a low temperature is most favour- 

 able to incipient fermentation, by which process the excess of 

 sweet matter in the flour may be changed into vinous spirit and 

 be dissipated in drying. My experiments have been too limited 

 to enable me to speak accurately concerning the relations of the 

 flour dried in different wavs, to vvater. I obtained one result 

 that was rather unexpected : — I shall state the experiment, but 

 as I had not an opportunity of repeating it I shall decline all com- 

 ment on it. I dried eleven ounces of bad new flour on a hot 

 hearth ; in six hours it had lost nearly two ounces. I made the 

 dry flour up into dough, but found that it required less water for 

 this purpose than an equal weight of the undried flour. 



The principal substances employed to improve the new flour 

 for bread appear to be the alkalies and their compounds, and the 

 subcarbonate of magnesia; and I pressume they have been found 

 more efficacious in this way, than any bodies that have yet been 

 tried. 



In my former communications I have recommended the use 

 of the subcarbonate of magnesia, and endeavoured to point out 

 its agency when emploved in bread. I shall now briefly state 

 some comparative experiments I made, which led me to recom- 

 mend magnesia in preference to any of the other alkaline sub- 

 stances. I made fourteen small loaves of the new seconds flour 

 of bad quality : each loaf contained half a pound of flour and 

 nearly the same quantity of yeast, salt, and warm water; 



No, 1. Loaf containing only the above substances; quite heavy 

 and so clammy as readily to adhere to a knife and the 

 fingers; — bad tasted. 



2. Loaf with ten grains of subcarbonate of ammonia in so- 

 lution ; — Lighter and better tasted than No. 1 . but rather 

 clam m v. 



3. Loaf with twenty grains stick potash (kali puriim); — Bet- 

 ter than No. L, but not so good as No. 2. 



4. Loaf with twenty grains subcarbonate potash ; — Pretty 



good, rather better than No. 2. 



5. Loaf with ten grains American potash j — Improved, but 

 not equal to No. 2. 



Vol. 49. No. 227. March 1817. M No. G. 



