Page:Memoirs of the Geological Survey of Great Britain, Volume 1.djvu/448

Rh second part of this paper, and which are intended to be preliminary to others, in which, as far as possible, the conditions observed in nature will be imitated, have been most carefully made. Although first in the order of date, many of these experiments having been completed in the autumn of 1845, I have thought it would be more satisfactory that they should follow the account of the effects produced by magnetism on molecular and crystalline forces, which appear to give us the key to the explanation of the other phenomena, than that they should precede it, particularly as the voltaic experiments must be regarded as merely isolated instances, which will require to be repeated under many forms, necessarily occupying a long period of time, before we shall be enabled to deduce any general conclusions from them.

5. In the Philosophical Magazine for January, 1846, I published a notice of some experiments, under the title of 'The Influence of Magnetism on Molecular Arrangement' The results obtained since the appearance of that paper confirm in a most striking manner, those so briefly described at that time, and the experiments have now been sufficiently numerous to enable us to deduce from them some general laws of action. It may appear that many of the experiments have no direct bearing on the question under consideration, and certainly, in the present state of the inquiry, they stand as isolated phenomena, but I have no doubt that we shall, as the examination is proceeded with, find that they are related to, and explanatory of, many of the great observed facts in nature.

6. Although the inquiry has recently acquired fresh interest from the extraordinary discoveries of Faraday on new magnetic actions, it must not be forgotten that some indications of such results as those I am about to describe, have been long since obtained, although the experiments attracted but a small share of attention, by Muschman of Christiana, and Hanstein. I would here also refer to some experiments of Ritter, analyzed by Œrsted, pointing out the difference, which I have constantly observed, existing between the influence by the north and south poles of a magnet on chemical action.

7. As it is of the first importance that a distinct understanding of the meaning of the terms employed in science should exist, it is necessary to explain that I shall adopt those terms which have been recently intro-