Queenwood College | near Stockbridge Hants | 26th Jan. 1853.
Dear Prof. Faraday,
Will you allow me to introduce to your notice an experiment I made in Berlin,1 which I thought very remarkable at the time, but which I have had no opportunity to follow up since. It appears to me to lead to the same conclusion, if it be not the same in principle as those you have recently made. – It proves that the law of decrease2 for iron is different from that of a salt of the metal. Do you not consider it probable that a difference of this kind between water and bismuth is the cause of the greater repulsion of the latter at an increased distance. As the bismuth is carried to a greater distance it may in fact be regarded as immersed in a new fluid altogether, and if the difference of repulsion between this fluid and the bismuth be greater than the corresponding difference near the poles the facts observed would of course follow.
I confess I never entertained the thought of applying the experiments described on the accompanying leaf3 as you have done, and though startled by the profound ingenuity of your argument on Friday night,4 for I did not imagine that the conclusion could be at all approached by the route chosen, the old magnetic law5 has still I confess a hold upon my convictions.
Believe me dear Sir | Most faithfully Yours | John Tyndall
APS Mss.Ms.Coll.200
Faraday Correspondence, 4:2630
Berlin: in 1851, Tyndall had spent time in the laboratory of Heinrich Magnus.
law of decrease: refers to the inverse-square law, which states that the decreased intensity of a magnetic force is inversely proportional to the square of its distance from the source of said force. Both Faraday’s and Tyndall’s independent experiments found that this did not uniformly apply for all magnetic bodies immersed in water. In some cases, as expected, at greater distance there was a decrease in repulsion, but in other cases there was an increase in the intensity of repulsion.
the accompanying leaf: not identified.
Friday night: Tyndall had attended Faraday’s lecture in London on 21 January. He described it in detail in his journal (JT/2/13b/596–7).
the old magnetic law: the inverse-square law.
Please cite as “Tyndall0708,” in Ɛpsilon: The John Tyndall Collection accessed on