1G2 JAMES cLEiiiv MAXWELL 



mathematical one, though not exhibited in the conventional 

 form of mathematical symbols. I also found that the.so 

 methods were capable of being expressed in the ordinary 

 mathematical forms, and thus compared with those of the pro- 

 fessed mathematicians. 



44 For instance, Faraday, in his mind's eye, saw lines of 

 force traversing all space where the mathematicians saw 

 centres of force attracting at a distance. Faraday saw a 

 medium where they saw nothing but distance. Faraday 

 sought the seat of the phenomena in real actions going on in 

 the medium. They were satisfied that they had found it 

 in a power of action at a distance impressed on the electric 

 fluid*" 



Now, Maxwell saw an analogy between electro- 

 statics and the steady motion of an incompressible 

 tluid like water, and it is this analogy which he develops 

 in the first part of his paper. T ho water Hows along 

 detinite lines; a surface which consists wholly of such 

 lines of flow will have the property that no water ever 

 crosses it. In any stream of water we can imagine a 

 number of such surfaces drawn, dividing it tip into a 

 scries of tubes; each of these will be a tube of flow, each 

 of these tubes remain always tilled with water. Hence, 

 the quantity of water which crosses per second any 

 section of a tube of flow perpendicular to its length is 

 always the same. Thus, from the form of the tuU\ 

 AVO can obtain information as "to the direction and 

 strength of the flow, for where the tube is wide the 

 flow will bo proportionately small, nnd elm /v/v?. 



Again, we can draw in the fluid a number of sur- 

 faces, over each of which the pressure is the same ; 

 these surfaces will cut the tubes of flow at right 

 angles. Let us suppose they are drawn so that tho 

 ditlerenco of pressure between any two consecutive 



