176 Observations on the Changes produced in the new IVheati 



is somewhat similar with preserved fruits l)cginiiin,s; to undergo 

 the acetous fermentation; when they are heated with more sugar, 

 this process is checked, and all further chemical changes are sus- 

 pended. Common salt and other saline substances, as is well 

 known, are powerful antiseptics when used in (juantity, but when 

 employed in small proportion they promote piitreraction. Sugar 

 in a similar way appears to retard or promote fermentation. 



The efficacy of the method recommended by Mr. Hatchett of 

 improving damaged and musty corn, by exposing it to the agency 

 of hot water, may in part depend upon its dissolving out a por- 

 tion of the saccharine as well as the musty matter of the grain. 



The means recommended to improve the new flour for making 

 bread, are 1. By drying the flour. 2. By mixing with the flour 

 or the dough some innocent and cheap material. The flour 

 may be dried either slowly, by exposing a large surface of it 

 before the fire for several hours, and occasionally turning it over; 

 or rapidly in an oven, or by the ao;ency of steam. With a view 

 to ascertain the most efficient mode of drying the flour. I made 

 the following experiments on new seconds of bad quality. 



Exp. 1. — One pound of flour in a shallow tin dish was placed 

 before the fire, and occasionally turned over. After twenty-four 

 hours it lost one ounce in weight. The bread from it was of a 

 better colour, lighter, and rather better-tasted than the flour 

 would have furnished before it was dried. Still, however, it had 

 a disagreeable taste, which was effectually corrected by the car- 

 bonate of magnesia, when used in the proportion of thirty grains 

 to a pound of the flour. 



Exp. 2. — One pound of flour in a tin dish was placed on an iron 

 plate for eight hours, at a temperature varying from about 200° 

 to 230\ It lost two ounces in weight. The bread from it was 

 not improved, but heavy, clammy, ami of a bad colour. 



Exp. 3. — One pound of flour in a dish was put into the oven 

 and exposed to a temperature varying from about 212'' to 250^ 

 for three hours ; it lost nearly an ounce in weight. The bread 

 from it was very little better than that of the preceding experi- 

 ment. 



To ascertain whether the flour, by being slowly dried, lost anv 

 thing besides moisture, I put two ounces of it into a tubulated 

 retort, placed the neck of the retort in a little distilled water, 

 and exposed the retort to the temperature of about 90^ for some 

 time. A little fluid came over. It was colourless and insipid, and. 

 did not aflfect litmus or turmeric paper ; and left no residuum 

 on being evaporated to dryness. . Hence it appeared to be only 

 water. — These experiments seem to favour the opinion that the 

 advantages resulting from drying the flour are best secured by 

 carrying on this process in a slow and gradual manner. And as 



the 



