teration, and in which the manufacturer so frequently 

 yields to the temptation. Not long ago the United 

 States government investigated the product of a sup- 

 posedly reputable firm which had been widely adver- 

 tised as a "pure lead-and-oil paint." The investigation 

 proved that there was not one grain of lead or one drop 

 of linseed oil in the much-heralded paint. From this it 

 will be correctly inferred that white lead is a relatively 

 expensive substance to produce. This production is 

 accomplished by many different processes, although all 

 of them are governed by the same general principle of 

 chemical action. 



Briefly stated, this is the action of acetic acid upon 

 metallic lead, producing a lead acetate, which is in turn 

 acted upon by carbonic acid and changed to a lead 

 carbonate. 



The three most commonly practised methods of man- 

 ufacture are known as the Dutch (or German, or 

 Austrian) process; the French process; and the English 

 process. In the Dutch process, metallic lead is used as a 

 basis ; in the French, lead acetate ; while in the English, 

 litharge (lead oxide) is used. When metallic lead is 

 used the metal is cast into sheets or strips, as metal 

 so treated is much more readily acted upon by the acid 

 than if pressed or drawn. 



The Dutch process is very old and very crude, but is 

 still used extensively in some countries, and has the merit 

 of making a good quality of white lead. In this process 

 the vessels containing metallic lead and acetic acid are 

 surrounded by manure, or by spent tan-bark, in a 

 closed chamber. The heat generated by the fermenta- 



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