Faraday continued to prosecute this newest line of research, and at the end of December, 1845, presented another memoir (the twenty-first series of the Experimental Researches) to the Royal Society. He had now examined the salts of iron, and had found that every salt and compound containing iron in the basic part was magnetic, both in the solid and in the liquid state. Even prussian-blue and green bottle-glass were magnetic. The solutions of the salts of iron were of special importance, since they furnish the means of making a magnet which is for the time liquid, transparent, and, within certain limits, adjustable in strength. His next step was to examine how bodies behaved when immersed in some surrounding medium. A weak solution of iron, enclosed in a very thin glass tube, though it pointed axially when hung in air, pointed equatorially when immersed in a stronger solution. A tube full of air pointed axially, and was attracted as if magnetic when surrounded with water. Substances such as bismuth, copper, and phosphorus are, however, highly diamagnetic when suspended _in vacuo_. Such a view would make _mere space_ magnetic. Hence Faraday inclined at first to the opinion that diamagnetics had a specific action antithetically distinct from ordinary magnetic action. Several times he pointed out that all the phenomena resolve themselves simply into this, that a portion of such matter as is termed diamagnetic tends to move from stronger to places or points of weaker force in the magnetic field. He does, indeed, hazard the suggestion that the phenomena might be explained on the assumption that there was a sort of diamagnetic polarity--that magnetic induction caused in them a contrary state to that which it produced in ordinary magnetic matter. But his own experiments failed to support this view, and, in opposition to Weber and Tyndall, he maintained afterwards the non-polar nature of diamagnetic action. In 1846 Faraday gave two Friday night discourses on these magnetic researches, one on the cohesive force of water, and one on Wheatstone’s electromagnetic chronoscope. At the conclusion of the last-named he said that he was induced to utter a speculation which had long been gaining strength in his mind, that perhaps those vibrations by which radiant energies, such as light, heat, actinic rays, etc., convey their force through space are not mere vibrations of an æther, but of the lines of force which, in his view, connect different masses, and so was inclined, in his own phrase, “to dismiss the æther.” In one of his other discourses he made the suggestion that we might “perhaps hereafter obtain magnetism from light.” [Sidenote: THOUGHTS ON RAY VIBRATIONS.]