The Correlation of Physical Forces: BEING THE SUBSTANCE OF A COURSE OF LECTURES DELIVERED IN THE LONDON INSTITUTION, IN THE YEAR 1843. Br W. R. GROVE, Esq., M.A., F.R.S. HONORARY MEMBER OF THE LONDON INSTITUTION. PRINTED BY ORDER OF THE MANAGERS OF THE LONDON M.DCCC.X L. VI. 199. PREFACE. THE subjects of the Course of Lectures embraced by the title of this sketch are much better adapted to oral than to written explanation; they demand at every step experimental illustration, and suggest questions which the Lecturer has an opportunity of answering, but which the writer cannot anticipate. Notwithstanding the manifold difficulties which surround the task, I am anxious to comply as far as in me lies with the wishes of the Proprietors of The London Institution, and to furnish them with a short resumé of some of those views of Physical Science which I have, in their Theatre, endeavoured to inculcate. of Although these views have not been lost sight of in any my Courses of Lectures, yet they were more prominently brought forward in the Course delivered in 1843, under the same title as heads this Essay; and it is a short exposition of the principles advanced in this Course, not a report of the Lectures themselves, which I am here attempting to set forth. As far as I am able, I shall give expression in this abstract to such views only as I offered at the time of the Lectures. In a Lecture which I gave in January, 1842, on the Progress of Physical Science (printed at the request of the Proprietors), I have briefly enunciated the propositions which were explained and illustrated by the Course of 1843, of which Course a tolerably full report appears in the Literary Gazette for January, 1844. As it would interrupt the consecutive developement of my own ideas were I frequently to quote, in the body of this paper, authorities either opposing or coinciding with them, and as I might also be charged with misconstruction of their views, I give, at the conclusion, references to such passages of different authors, published previously to my Lectures, as I have, since their date, found in any way bearing upon the views I have ventured to put forth: most of these were kindly furnished me by Mr. Brayley. My professional occupations having compelled me to resign an office which I held for five years, I cannot let this opportunity pass without expressing my grateful sense of the uniform kindness I have received from the Proprietors of The London Institution. 4, Hare Court, Temple, August 31, 1846. CORRELATION OF PHYSICAL FORCES. WHEN natural phenomena are for the first time observed, a tendency immediately developes itself to refer them to something previously known,-to bring them within the range of acknowledged sequences. The mode of regarding new facts, which is most favourably received by the public, is that which refers them to recognised views,-stamps them into the mould in which the mind has been already shaped. The new fact may be far removed from those to which it is referred, and may belong to a different order of analogies, but this cannot then be known, as its co-ordinates are wanting. It may be questionable whether the mind is not so moulded by past events that it is impossible to advance an entirely new view, but, admitting such possibility, the new view, necessarily founded on insufficient data, is likely to be more incorrect and prejudicial than even a strained attempt to reconcile the new discovery with known facts. The theory consequent upon new facts, whether it be a co-ordination of them with known ones, or the more difficult and dangerous attempt at remodelling the public ideas, is generally enunciated by the discoverers themselves of the facts, or by those to whose authority the world at that B |