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tlonalia of the Subject they are engaged in;I would therefore recommend the Perusalof the following Books to such as are notthus qualified ; viz. The last Edition ofJBoerhaaves Chymistry, with Dr. Shaw’sNotes; Dr. Stahl’s Chymistry, translatedby Dr. Shaw ; and Dr. Cramer’s Elementsof Aslaying Metals ; and these not only tobe read and considered of, but that alsothey should -at the tame Time make theExperiments, and perform the Processestherein mentioned ; for one is not sufficientwithout the other to make them compre-hend those Works: By these co-aidingMeans, I am satisfied they will be enabledto make some Progress; and if any Booksmore advanced in this Science shall here-after be published, by pursuing the aboveMethod, they will be enabled to ^under-stand and go through the Processes con-tained in them. I am,

S IF,

Tour obedient Servant,

Diederick Whssel Linden.

Holywell, in Flintshire,

Oct. 23, 1749.

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LETTER