228 SCIENCE IN, SHORT CHAPTERS. 



of pounds in 1872, were green, the rest black. This gives 

 in round numbers about 160 millions of pounds of black tea 

 per annum, of which above 140 millions come from China. 

 As the Eussians are greater tea-drinkers than ourselves the 

 Americans and British colonists are at least equally addicted 

 to the beverage, and other nations consume some quantity 

 the total exports from China may be safely estimated to reach 

 400 or 500 millions of pounds. a 



Let us take the smaller figure, and suppose that only one 

 fourth of this is adulterated, o the extent of 5 per cent, 

 with iron filings. How much would be required ? Just five 

 millions of pounds per annum. 



It must be remembered that coarse filings could not pos- 

 sibly be used; they would show themselves at once to the 

 naked eye as rusty lamps, and would shake down to the 

 bottom of the chest; neither could borings, nor turnings, 

 nor plane-shavings be used. Nothing but fine filings would 

 answer the supposed purpose. I venture to assert that if 

 the China tea-growers were to put the whole world under 

 contribution for their supposed supply of fine iron filings, 

 this quantity could not be obtained. 



Let anyone who doubts this borrow a blacksmith's vice, 

 a fine file, and a piece of soft iron, then take off his coat and 

 try how much labor will be required to produce a single 

 ounce of filings, and also bear in mind that fine files are but 

 very little used in the manufacture of iron. As the price of 

 a commodity rises when the demand exceeds the supply 

 the Chinaman would have to pay far more for his adulterant 

 than for the leaves to be adulterated. As Chinese tea- 

 growers are not public analysts, we have no right to sup- 

 pose that they would perpetrate any such foolishness. 



The investigations recently made by Mr. Alfred Bird, of 

 Birmingham, show that the iron found in tea-leaves is not 

 in the metallic state, but in the condition of oxide; and he 

 confirms the conclusions of Zoller, quoted by Mr. J. A. 

 Wanklyn in the Chemical News of October 10th viz., that 

 compounds of iron naturally exist in genuine tea. It ap- 

 pears, however, that the ash of many samples of black tea 

 contains more iron than naturally belongs to the plant; and, 

 accepting Mr. Bird's statement," that this exists in the leaf 



