ELECTRICITY. 373 



You may mix a quantity of hog's-lard with it by 

 rubbing in a mortar, adding to it a small portion 

 of whitening, and about a fifth of the above- 

 mentioned amalgam of tin. 



OF ANIMAL ELECTRICITY. 



By animal electricity, we mean the electricity 

 that is produced by the voluntary action of the 

 organs of living animals. 



Fishes are the only animals yet known to possess 

 the wonderful property of being able at pleasure to 

 give a shock analogous to that produced by 

 artificial electricity. Of these we are acquainted 

 with three species, viz. the torpedo, the gymnotus 

 elections, and the silurus electricus. 



The torpedo is a flat fish, very seldom *20 inches 

 long, weighing not above a few pounds when full 

 grown, and is common in various parts of the sea- 

 coast of Europe. The electric organs of this 

 animal are two in number, and are placed on each 

 side of the gills. Each organ consists of perpen- 

 dicular columns, reaching from the under to the 

 upper surface of the body, and varying in length 

 according to the thickness of the fish in different 

 parts. The number of these columns varies in 

 different torpedos, and also in different ages of 

 the animal. 



If the torpedo, whilst standing in water, or out 

 of it, but not insulated, be touched with one hand, 

 it generally communicates a trembling motion, or 

 slight shock to the hand; but the sensation is felt 

 in the fingers of that hand only. If the torpedo be 

 touched with both hands at the same time, one 

 being applied to its under, and the other to its 

 upper surface, a shock in that case will be received, 



BB'3 



