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XXXIX. Chemical Experiments and Obfervations on Lead 
Ore. By Richard Watfon, D. D. F. R. S . in a Letter 
to Sir John Pringle, Bart. P. R. S. 
1 
TO SIR JOHN PRINGLE, BART. P. R. 5 . 
SIR, 
Cambridge, 
June i 3 , 1 77?, 
Read July 9, r g Ijje following experiments and obferva- 
tions, it is apprehended, will not be 
thought uninterefting by perfons verfed in chemiftry. 
May I beg the favour of you to communicate them to 
the Royal Society l 
I am, Sec. 
LEAD ORE, as dug out of the mine, is generally 
much mixed with fpar, lime-ftone, and other fubftances, 
bulk for bulk, heavier than the ore itfelf. It undergoes 
various dreffings before it becomes a merchantable com- 
modity, the general tendency of which is to free it, as 
much as poffible, from every heterogeneous impurity. 
Suppofe 
