By such means, only, is the great earthquake to be accounted for on dynamic principles. Far as the subterraneous grumbling extends, the physical cause must be present, and in a state of force equal to the awful result. No pent-up air suddenly set free, or suddenly exploded gas,--both naturally forceless,--subject to attenuation and obstruction in the passage from the source--is competent to burst the globe and hurl whole cities into the engulfing chasm: nor is fire any assistant, judging from the absence of flame, smoke, cinders, and ashes. Dreadful as is the catastrophe, it is but a natural casuality and in perfect accordance with the laws of matter. An extraordinary rushing into the body of the earth of medium of space, preceded by an equal efflux of elementary matter atmospherically induced, are the cause and promoting means of the extraordinary, terrific phenomenon. All things being under the general pressure, and elementary atoms of all sizes everywhere present, the interstices of bodies cannot remain empty. From all interstices being formed by spherical atoms, and the atoms of the medium of space the smallest, there are always interstitial spaces for medium of space to enter, pass through or remain within, and which _is not insulated_, but continuous with the outward source. Thus, has the medium of space access to every atom, and by the pressure from without, is enabled to act _centrifugally_ within the body, as a kind of back-spring against each and the whole of its constituent atoms, to produce expansion, dissolution, and elementary dispersion according to the medium or circumstances in which the body may be placed. These general principles admit of repetition, in order, that, by repeated showing, to prove their validity, against others more generally known and adopted, although unfounded in nature, sense, or reason. MINUS-PRESSURE MATTER. Taking the maximum of pressure as a fixed quantity, or, as not being subject to increase, and assuming the degree to be not less than equal to the tenacity of steel, there must of necessity be means of mitigating the maximum, so that in the scale of descent every degree of force should be attainable; and more, to keep the equilibrium in a state of disturbance, without which all things must be, and remain in the rest of death. Were there no minus-pressure means, the solid, or perhaps aëriform state of matter would exist everywhere, and of motion there could be none. Such means for promoting motion are amply supplied, and without any addition of matter to the measured quantity sufficient for the formation of bodies and service of nature generally, in the elements themselves, of matter.