276 Mr. Faraday o?i Chemical Manipulation, 



substantiate our judgment by quotations, in consequence of 

 the general didactic character of the book, and the mutual 

 dependence and connexion of its different parts. We shall 

 attempt, however, to give the general reader an outline of its 

 contents, and point out such parts to the chemist as we con- 

 ceive particularly useful and worthy attention. 



The importance of readiness and dexterity in the perform- 

 ance of experiments has been duly estimated for more than 

 a century. The writings of Black, Cavendish, Priestley, and 

 especially Scheele, as opposed to those of their predecessors, 

 show that they had acquired considerable facility in attaining, 

 by simple and economical means, those ends which had before 

 consumed much time and much expense in their accomplish- 

 ment: but it is only of late years that the refinements of 

 manipulation have been carried towards perfection ; and the 

 researches carried on in the laboratory of the Royal Institu- 

 tion have been not a little conducive to this improvement : 

 to no one, however, is this part of the science more indebted 

 than to Dr. Wollaston, whose skill in what may be called 

 microscopic chemistry is consummate, and who has a host of 

 humble but industrious imitators. So essential, indeed, is 

 the attainment of correct methods of manipulation to the 

 progress of chemical science, that many entire trains of 

 research are exclusively dependent upon it for success. It is 

 true that it must always be subordinate to genius and inven- 

 tion ; yet the person who could only devise, without knowing 

 how to perform, would comparatively be able to lend little 

 aid to the extension and usefulness of knowledge : and were it 

 not an invidious task, we might be able to show that some of 

 the greatest discoveries and improvements of the science 

 have originated in dexterity of experiment, rather than in 

 profundity of design. By tact, therefore, in manipulation, a 

 considerable advantage is gained, independent of that result- 

 ing from an acquaintance with the principles of the science ; 

 and this is so considerable, that, of two persons of equal 

 talent and information in other respects, he who is the best 

 manipulator will soon be in advance of the other ; the one 

 "will draw just inferences with accuracy and rapidity, while 

 the other will be lost in doubt, and often led into error. 

 Mr. Faraday has pointed out several other cases of prominent 

 advantage, arising from skilful manipulation, especially when 

 very small quantities of matter are to be operated upon, and 

 where accurate conclusions are of more than ordinary import- 

 ance, as in testing for arsenic and other poisons on judicial 

 occasions. When the substance under examination is rare. 



