1. A more perfect apprehension of those subtile agencies, the effects of which are continually present in various operations of nature, seems of paramount importance to the future advancement of science. Thus the physical causes of heat, light, electricity and magnetism, have become subjects of deep interest to the natural philosopher; little apology, therefore, may perhaps be deemed requisite for my venturing to submit to the consideration of the Royal Society an account of some inquiries, the object of which is to improve our knowledge of one of these great natural powers. As it is only by a patient and repeated induction from well investigated facts that we can hope to attain a higher degree of perfection in natural knowledge, I have thought it not altogether undesirable to inquire further into the elementary laws of common electricity: indeed, upon considering the late fine discoveries of Dr. Faraday, this seems to a certain extent requisite. The researches of this distinguished philosopher have invested electrical phenomena generally with a new interest, and exposed novel and important features in the theory of electrical action. The investigations in this department of science, which I have now the honour of presenting to the Royal Society, will, I hope, be found to contain matter of sufficient interest to render them not unworthy of its acceptance.