68 FEAGMENTS OF SCIENCE. 



any vegetable, perfected in a minute before your eyes. 

 Substituting for the nitrate of silver acetate of lead, 

 which is a compound of lead and acetic acid, the elec- 

 tric 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 our earth ' brute matter,' as Dr. Young, in his 

 Night Thoughts, is pleased to call it when its atoms 

 and molecules are permitted to bring their forces into 

 free play, arranges itself, under the operation of these 

 forces, into forms which rival in beauty those of the 

 vegetable world. And what is the vegetable world 

 itself, but the result of the complex play of these molec- 

 ular forces? Here, as elsewhere throughout nature, 

 if matter moves it is force that moves it, and if a cer- 

 tain structure, vegetable or mineral, is produced, it is 

 through the operation of the forces exerted between 

 the atoms and molecules. 



The solid matter of which our lead and silver trees 

 were formed was, in the first instance, disguised in a 

 transparent liquid; the solid matter of which our woods 

 and forests are composed is also, for the most part dis- 

 guised in transparent gas, which is mixed in small 

 quantities with the air of our atmosphere. This gas is 

 formed by the union of carbon and oxygen, and is 

 called carbonic acid gas. The carbonic acid of the air 

 being subjected to an action somewhat analogous to 

 that of the electric current in the case of our lead and 

 silver solutions, has its carbon liberated and deposited 

 as woody fibre. The watery vapour of the air is sub- 

 jected to similar action; its hydrogen is liberated from 

 its oxygen, and lies down side by side with the carbon 

 in the tissues of the tree. The oxygen in both cases is 



