MATTER AND FORCE 73 



beautiful forms. With another solution we obtain crys- 

 talline spears, feathered right and left bj other spears. 

 From distant nuclei in the middle of the field of view 

 the spears shoot with magical rapidity in all directions. 

 The film of water on a window-pane on a frosty morning 

 exhibits effects quite as wonderful as these. Latent in 

 these formless solutions, latent in every drop of water, 

 lies this marvellous structural power, which only requires 

 the withdrawal of opposing forces to bring it into action. 



The clear liquid now held up before you is a solution 

 of nitrate of silver — a compound of silver and nitric acid. 

 When an electric current is sent through this liquid the 

 silver is severed from the acid, as the hydrogen was sep- 

 arated from the oxygen in a former experiment; and I 

 would ask you to observe how the metal behaves when 

 its molecules are thus successively set free. The image 

 of the cell, and of the two wires which dip into the 

 liquid of the cell, are now clearly shown upon the 

 screen. Let us close the circuit, and send the current 

 through the liquid. From one of the wires a beautiful 

 silver tree commences immediately to sprout. Branches 

 of the metal are thrown out, and umbrageous foliage 

 loads the branches. You have here a growth, appar- 

 ently as wonderful as that of any vegetable, perfected 

 in a minute before your eyes. Substituting for the ni- 

 trate of silver acetate of lead, which is a compound of 

 lead and acetic acid, the electric current severs the lead 

 from the acid, and you see the metal slowly branching 

 into exquisite metallic ferns, the fronds of which, as they 

 become too heavy, break from their roots and fall to the 

 bottom of the cell. 



These experiments show that the common matter of 

 Science — VI — 4 



