FREE BOOKS

Author's List




PREV.   NEXT  
|<   53   54   55   56   57   58   59   60   61   62   63   64   65   66   67   68   69   70   71   72   73   74   75   76   77  
78   79   80   81   82   83   84   85   86   87   88   89   90   91   92   93   94   95   96   97   98   99   100   101   102   >>   >|  
spended, it always set axially, that is, from pole to pole. Faraday called those bodies which were repelled by the poles of a magnet, diamagnetic bodies; using this term in a sense different from that in which he employed it in his memoir on the magnetization of light. The term magnetic he reserved for bodies which exhibited the ordinary attraction. He afterwards employed the term magnetic to cover the whole phenomena of attraction and repulsion, and used the word paramagnetic to designate such magnetic action as is exhibited by iron. Isolated observations by Brugmanns, Becquerel, Le Baillif, Saigy, and Seebeck had indicated the existence of a repulsive force exercised by the magnet on two or three substances; but these observations, which were unknown to Faraday, had been permitted to remain without extension or examination. Having laid hold of the fact of repulsion, Faraday immediately expanded and multiplied it. He subjected bodies of the most varied qualities to the action of his magnet:--mineral salts, acids, alkalis, ethers, alcohols, aqueous solutions, glass, phosphorus, resins, oils, essences, vegetable and animal tissues, and found them all amenable to magnetic influence. No known solid or liquid proved insensible to the magnetic power when developed in sufficient strength. All the tissues of the human body, the blood--though it contains iron--included, were proved to be diamagnetic. So that if you could suspend a man between the poles of a magnet, his extremities would retreat from the poles until his length became equatorial. Soon after he had commenced his researches on diamagnetism, Faraday noticed a remarkable phenomenon which first crossed my own path in the following way: In the year 1849, while working in the cabinet of my friend, Professor Knoblauch, of Marburg, I suspended a small copper coin between the poles of an electro-magnet. On exciting the magnet, the coin moved towards the poles and then suddenly stopped, as if it had struck against a cushion. On breaking the circuit, the coin was repelled, the revulsion being so violent as to cause it to spin several times round its axis of suspension. A Silber-groschen similarly suspended exhibited the same deportment. For a moment I thought this a new discovery; but on looking over the literature of the subject, it appeared that Faraday had observed, multiplied, and explained the same effect during his researches on diamagnetism. His explanation was b
PREV.   NEXT  
|<   53   54   55   56   57   58   59   60   61   62   63   64   65   66   67   68   69   70   71   72   73   74   75   76   77  
78   79   80   81   82   83   84   85   86   87   88   89   90   91   92   93   94   95   96   97   98   99   100   101   102   >>   >|  



Top keywords:

magnet

 

magnetic

 

Faraday

 
bodies
 

exhibited

 

observations

 

attraction

 
researches
 

diamagnetism

 

tissues


action

 

repulsion

 
employed
 

multiplied

 

proved

 
diamagnetic
 

suspended

 

repelled

 

cabinet

 

copper


friend
 

Professor

 
Marburg
 

working

 

Knoblauch

 

extremities

 

retreat

 

suspend

 
length
 

phenomenon


crossed
 

remarkable

 

noticed

 

equatorial

 
commenced
 

violent

 

moment

 

thought

 
discovery
 

deportment


Silber

 

groschen

 

similarly

 

explanation

 
effect
 

explained

 

literature

 

subject

 
appeared
 

observed