B'tographical Memoir of the late Dr Turner. --^7 



character of umpire between two of the greatest of living che- 

 mists. 



Chemistry has to thank, two distinct classes of philosophers for 

 the extraordinary extension of her modern boundaries. To the 

 one belongs the discoverer, the inventor, the original genius ; to 

 the other, the man of minute observation, of cautious judgment, 

 of profound learning, the analyst, the author. To which oi; 

 these two classes the science stands most deeply indebted, it may 

 be difficult to say. Little progress, however, could be maae 

 without both ; for the qualities of both seldom pre-eminently 

 co-exist in the same individual. In the latter denomination, Dr 

 Turner was content to rank himself. Throughout his whole 

 scientific life he appears, not as the brilliant discoverer, astonish- 

 ing the imagination, but as the exact, the cautious observer, 

 satisfying the judgment ; and in no capacity has he shone more 

 than in that, which he early and chiefly chose for himself, of an 

 impartial umpire, to fix definitely those boundaries of know- 

 ledge which others of more inventiveness had vaguely or dubi- 

 ously indicated. That he thus duly estimated and happily ap- 

 plied his peculiar gifts, we learn, not more from the internal evi- 

 dence of his researches, than from his own declaration. " The 

 time is arrived,'" says he, in the introduction of the paper I am 

 now to describe, " for reviewing our stock of information, and 

 submitting the principal facts and fundamental doctrines of the 

 science to the severest scrutiny. The activity of chemists should 

 now, I conceive, be specially employed, not so much in search- 

 ing for new compounds or new elements, as in examining those 

 already discovered ; in ascertaining, with the greatest possible 

 care, the exact ratio in which the elements of compounds are 

 united ; in correcting the erroneous statements to wliich inaccu- 

 rate observation has given rise ; and in exposing the fallacy of 

 opinions which partial experience or false facts have produced. 

 Considerable as is the labour and difiiculty of such researches, 

 they will eventually prove of great importance to chemical science 

 by supplying correct materials for reasoning." * 



It was with such views and feelings that Dr Turner com- 

 menced his inquiry into the constitution of the Chloride of 

 Barium. 



" Philosophical Transaction?, 18-i9, cxix. 291. 



