Prof. Faraday on some Points of Magnetic Philosophy, 93 



itself; and those who assume that electric currents are the cause 

 of magnetic effects, would have to give up the law of their in- 

 ducing action (as far as we know it) in all cases of diamagnetism, 

 at the very same moment when, if they approached the diamag- 

 netic bismuth in the form of a spiral to the pole, they would 

 have a current produced in it according to that law. 



Time. 



3318. I will venture another thought or two regarding the 

 condition into which diamagnetic bodies are brought by the act 

 of magnetic induction, in connexion with the point of time. It 

 appears, as far as I remember, that all natural forces tend to 

 produce a state of rest, except in cases where vital or organic 

 powers are concerned ; and that as in life the actions are for ever 

 progressive, and have respect to a future rather than a present 

 state (Paget), so all inorganic exertions of force tend to bring 

 about a stable and permanent condition, having as the result a 

 state of rest, i. e. a static condition of the powers. 



3319. Applying this consideration to the case of bismuth in 

 the magnetic field, it seems to me more like the truth of nature 

 that the state assumed by the bismuth should be one more 

 favourable to the final and static exercise of the power of the 

 dominant magnet upon it, than that state belonging to the bis- 

 muth before it had suffered or undergone the induction ; exactly 

 as in soft iron we know that before it has acquired the state 

 which a dominant magnet can induce upon it, it is not so favour- 

 able to the final static condition of the powers as it is afterwards. 

 Now it is very manifest, by numerous forms of experiment, that 

 time enters as an element into ordinary magnetic and magneto- 

 electric actions, and there is every reason to expect into diamag- 

 netic actions also; and it is also well known that we can take 

 advantage of this time, and test the state of a piece of iron in 

 the magnetic field before it has attained its finally induced state, 

 and afterwards; — as, for instance, by placing it with a helix round 

 it in the magnetic field and quickly connecting the helix afterwards 

 with a galvanometer, when a current of electricity in such direc- 

 tion as to prove the truth of the statement will be obtained. In 

 other forms of experiment, and with large pieces of iron, the 

 time which can be so separated or snatched up during the act of 

 progressive induction will amount to a minute or more. Sup- 

 posing this could be done in any sensible degree with diamag- 

 netic bodies, then the following considerations present them- 

 selves. A globe or bar of bismuth in the magnetic field may 

 have its states, before and after induction, considered as sepa- 

 rated by a moment of time ; if the induction raises up a state of 

 polarity the reverse of that of the magnet, then the bismuth 



