the theory does assume ; as, for instance, that all particles, whether of insulators or conductors, are, as wholes, conductors ; that, being conductors, they can readily be charged either bodily or polarly ; that contiguous particles being on the line of inductive action can communicate their forces more or less readily ; that those doing so most readily constitute the bodies called conductors, and those do- ing so least readily those called insulators, &c.
Having thus given a brief summary of the conclusions drawn from the previous investigations, the author proceeds to consider the particular condition of the particles which, in an insulating body, are considered as polarized ; and after showing that the theory requires that they should be able to polarize in any di- rection, he states his expectation that a greater facility to polarize in one direction than another would still be found to belong to them, and proceeds experimentally to determine this point. His ex- periments were made by observing the degree of inductive force across cubes of perfectly crystallized bodies, as rock crystal and Iceland spar ; these being cut so as to have the axis of the crystal parallel to the line joining two opposite faces of the cube; but the experiments, which are laborious, require extension, and he has not as yet been able to prove or disprove the expected result.
The author then considers whether in compound bodies it is the ultimate and elementary particles or the compound particles which polarize as wholes. He concludes that it is the latter which assume that state ; and shows how this point bears upon the electrolyzation of such bodies as are separated into simpler substances, or otherwise altered by the action of the voltaic current.
He then proceeds to certain experiments bearing upon the nature of the relation of the electric and magnetic forces, giving his view, of the character of this relation ; and concludes his paper by briefly stating what he thinks is more satisfactorily explained by the theory which refers inductive action to an action of contiguous particles than by the old theory.
"Experiments on the Vibration of the Pendulum." By W. J. Frodsham. Communicated by Francis Beaufort, Capt. R.N., F.R.S.
The object of this paper is to show the advantages that may re- sult from attaching to the top of the pendulum a brass tube, which the author terms " an isochronal piece," about five inches in length, fitting the pendulum very nicely, and slit so as to form a spring for about an inch at the bottom, sliding rather stiffly on the rod, so that its position, and consequently its influence on the action of the pendulum, maybe varied at pleasure; and that unequal arcs of vibra- tion may be made to correspond to equal intervals of time.
"An Account of some Experiments on the Blood in connexion with the Theory of Respiration." By John Davy, M.D., F.R.S., Assistant Inspector of Army Hospitals.
The author has investigated, experimentally, several of the important questions connected with the theory of respiration and of
