MENTAL QUALIFICATIONS FOR THE INQUIRY. 377 



duction, though with polarity), or by an ether pervading all 

 parts of space, than admit that the conservation of force 

 could be dispensed with. 



It may be supposed, that one who has little or no mathe- 

 matical knowledge should hardly assume a right to judge of 

 the generality and force of a principle such as that which 

 forms the subject of these remarks. My apology is this : I 

 do not perceive that a mathematical mind, simply as such, has 

 any advantage over an equally acute mind not mathematical, 

 in perceiving the nature and power of a natural principle of 

 action. It cannot of itself introduce the knowledge of any 

 new principle. Dealing with any and every amount of static 

 electricity, the mathematical mind has balanced and adjusted 

 them with wonderful advantage, and has foretold results 

 which the experimentalist can do no more than verify. But 

 it could not discover dynamic-electricity, nor electro-magnet- 

 ism, nor magneto-electricity, or even suggest them ; though 

 when once discovered by the experimentalist, it can take them 

 up with extreme facility. 



So in respect of the force of gravitation, it has calculated 

 the results of the power in such a wonderful manner as to 

 trace the known planets through their courses and perturba- 

 tions, and in so doing has discovered a planet before unknown ; 

 but there may be results of the gravitating force of other 

 kinds than attraction inversely as the square of the distance, 

 of which it knows nothing, can discover nothing, and can 

 neither assert nor deny their possibility or occurrence. Under 

 these circumstances, a principle which may be accepted as 

 equally strict with mathematical knowledge, comprehensible 

 without it, applicable by all in their philosophical logic, what- 

 ever form that may take, and above all, suggestive, encour- 

 aging, and instructive to the mind of the experimentalist, 

 should be the more earnestly employed and the more fre- 

 quently resorted to when we are labouring either to discover 

 new regions of science, or to map out and develop those 



