DESCRIPTION OF GALVANIC BATTERIES, 



AND THEIR RESPECTIVE PECULIARITIES. 



Nomenclature. The terms that are employed to denote the vari- 

 ous parts of a galvanic battery, and of other electrotype arrangements, 

 frequently puzzle the student, and lead him into difficulties. Before 

 we proceed to describe the various forms of the battery, we shall, 

 for this reason, give a preliminary account of the nomenclature of 

 galvanism. 



The two extremities of a battery have long been called Poles; one 

 of them the Positive, and the other the Negative, Pole. But objec- 

 tions have been taken to the use of the terms negative, positive, and 

 pole, on the ground that such terms do not convey a correct idea of 

 the circumstances or of the effects produced. Before connecting the 

 two metals or extremities of a battery, no electricity is evolved, and 

 when the connection is formed the electricity simply makes a circuit, 

 but it is stated, or rather supposed, that no particular portion of 

 that circuit can be said to be either negative or positive to another 

 portion. 



Proposed Terms. Various terms have been suggested as substi- 

 tutes for negative and positive, and also for pole. Dr. Faraday has 

 proposed the following : for pole, he substitutes electrode, which 

 signifies a way; for the negative pole, cathode, signifying downwards; 

 and for the positive pole, anode, or upwards. To understand these 

 terms properly, we must suppose a battery lying upon the ground 

 with its copper (positive) end to the east, and the wire connecting 

 the ends of the battery bent into an arch similar to the course of the 

 sun ; the electric current will thus flow up from the east end of the 

 battery, and descend into it at the west end. The fluid that is 

 decomposed by a current passing through it is termed by Faraday 

 an electrolyte; the elements liberated by this decomposition he terms 

 ions, distinguishing those liberated at the cathode as cations, which 

 in sulphate of copper would be the metal, and those liberated at the 

 anode as anions, which would be the acid portion of the sulphate of 

 copper. 



