230 SCIENCE IN SHORT CHAPTERS. 



jurious to health, then all other operations of dyeing are also 

 adulterations; for the other dyers, like the Chinaman, add 

 certain impurities to their goods the silk, wool, or cotton 



in order to alter their natural appearance, and to give 



them the. false facing which their customers demand, but 

 with this difference, if I am right in the above explanation: 

 that in darkening tea nothing more is done but to increase 

 the proportion of one of its natural ingredients, and to in- 

 tensify its natural color; while in the dyeing of silk, cotton, 

 or wool, ingredients are added which are quite foreign and 

 unnatural, and the natural color of the substance is alto- 

 gether falsified. 



The above appeared in the Chemical News November 

 21, 1873, when the adulteration in question was generally 

 believed to be commonly perpetrated, and many unfor- 

 tunate shop-keepers had been and were still being sum- 

 moned to appear at Petty Sessions, etc., and publicly 

 branded as fraudulent adulterators on the evidence of the 

 newly-fledged public analysts, who confidently asserted that 

 they found such filings mixed with the tea. Some discus- 

 sion followed in subsequent numbers of the Chemical Neivs; 

 but it only brought out the fact that " finely divided iron" 

 exists in considerable quantities in Sheffield, may be 

 "begged," as Mr. Alfred H. Allen (an able analytical 

 chemist, resident in Sheffield,) said. The fact that such 

 finely divided iron is thus without commercial value still 

 further confirms my conclusion that it is not used for the 

 adulteration of tea. If it were, its collection would be a 

 regular business, and truck-loads would be transmitted from 

 Sheffield to London, the great centre of - tea-importation. 

 No_ evidence of any commercial transactions in iron filings 

 or iron dust for such purposes came forward in reply to my 

 challenge. 



The practical result of the controversy is that iron filings 

 are no longer to be found in the analytical reports of the 

 adulteration of tea. 



