2TO Use of Sulphate of Copper^ 8fc. in Bread. 



The author divides his essay into two parts ; in ihe first he treats 

 of the origin of the use of those materials which are employed in 

 adulterations, of the proportions of them which have been adopted 

 by bakers, of the effects they produce, and of the methods he has 

 found most effectual for detecting their presence, even in minimum 

 quantities ;— in the second, he determines the action which these dif- 

 ferent substances exert upon the quality of bread. This was effected 

 by baking a very great number of loaves with variable proportions of 

 the adukerating materials. 



PART FIRST. 



The north of .France and BBlgium has been for some time past 

 the principal theatre of frauds committed by bakers, by the mixing 

 of sulphate of copper with their bread. The practice appears to 

 have commenced about 1816 and 1817, in which years the grain 

 was generally of a bad quality. To obviate this inconvenience, they 

 mixed with the wheat flour, the flour of dry beans and other sub- 

 stances, and at length made use of blue vitriol, finding that it contri- 

 buted to hasten the fermentation, to cause the dough to retain more 

 water, to diminish the labor of kneading, and produce a lighter and 

 finer looking bread from the defective or the mixed flour.* The 

 abuse was afterwards carried to such an extent, that in some of the 

 towns, commissioners were chosen to have the permanent supervision 

 of the bread made and sold by bakers. 



If the detection and punishment of so serious a crime as the poi- 

 soning of bread is a matter of importance to the public welfare, it is 

 also very necessary to be able clearly to demonstrate the presence of 

 the poisonous material. The detection of copper in bread would 

 seem to present no difficulty, as this metal manifests its presence by 

 decisive chemical characters. The contact of sulphuretted hydro- 

 gen, hydro-ferrocyanate of potash, or ammoniacal gas, may remove 

 all uncertainty ; but v/hen It is considered in how small a proportion 

 this poisonous salt is employed, these experiments demand the most 

 careful attention. Prussiate of potash indeed will indicate the pres- 

 ence of one part of sulphate in nine thousand parts of white bread, by 

 the production of a rose color in the containing fluid. The author 

 obtained the following results. 



* Thirteen bakers were condemned on the 27th of January, 1829, by the cor- 

 rectional tribunal of Brussels, for mixing sulphate of copper with their bread. 



