88 Presidential Address 



solid circuit round the current) . He would 

 see a sort of bridge or filament thus con- 

 structed, from one shore to the other, and 

 across this bridge insect-like things crawl- 

 ing and returning for no very obvious 

 reason. 



Or let him look at the Nile, and recog- 

 nise the meritorious character of that 

 river in promoting the growth of vegeta- 

 tion in the desert. Then let him see a 

 kind of untoward crystallisation growing 

 across and beginning to dam the benefi- 

 cent stream. Blocks fly to their places 

 by some kind of polar forces; "we cannot 

 doubt" that it is by helio- or other tropism. 

 There is no need to go outside the laws of 

 mechanics and physics, there is no diffi- 

 culty about supply of energy none what- 

 ever, materials in tin cans are consumed 

 which amply account for all the energy; 

 and all the laws of physics are obeyed. 

 The absence of any design, too, is mani- 

 fest; for the effect of the structure is to 

 flood an area upsteam which might have 

 been useful, and to submerge a structure 

 of some beauty; while down stream its 



