484 On Mental Education. [1855. 



stated most clearly all the conditions, and resolved the forces 

 into three directions ; but not perceiving the physical cause of 

 the action, exercised a most wise and instructive reservation as 

 to his conclusion. Others, as Haldat, considered it as the 

 proof of the universality of a magnetism of the ordinary kind, 

 and held to that notion though it was contradicted by the 

 further facts ; and it was only at a future period that the true 

 physical cause, namely, magneto-electric currents induced in 

 the copper, became known to us*. What an education Arago's 

 mind must have received in relation to philosophical reservation ; 

 what an antithesis he forms with the mass of table-turners ; 

 and what a fine example he has left us of that condition of 

 judgment to which we should strive to attain ! 



If I may give another illustration of the needful reservation 

 of judgment, I will quote the case of oxygen and hydrogen 

 gases, which, being mixed, will remain together uncombined 

 for years in contact with glass, but in contact with spongy pla- 

 tinum combine at once. We have the same fact in many forms, 

 and many suggestions have been made as to the mode of action ; 

 butasyet we do not know clearly how the result comes to pass. 

 We cannot tell whether electricity acts or not. Then we should 

 suspend our conclusions. Our knowledge of the fact itself, 

 and the many varieties of it, is not the less abundant or sure ; 

 and when the truth shall hereafter emerge from the mist, 

 we ought to have no opposing prejudice, but be prepared to 

 receive it. 



The education which I advocate will require patience and 

 labour of thought in every exercise tending to improve the 

 judgment. It matters not on what subject a person's mind is 

 occupied, he should engage in it with the conviction that it will 

 require mental labour. A powerful mind will be able to draw 

 a conclusion more readily and more correctly than one of mode- 

 rate character ; but both will surpass themselves if they make an 

 earnest, careful investigation, instead of a careless or prejudiced 

 one ; and education for this purpose is the more necessary for 

 the latter, because the man of less ability may, through it, raise 

 his rank and amend his position. I earnestly urge this point 

 of self-education, for I believe it to be more or less in the power 

 of every man greatly to improve his judgment. I do not think 

 * Philosophical Transactions, 1832, p. 146. 



