14. This rhythm of evolution and dissolution, completing itself during short periods in small aggregates, and in the vast aggregates distributed through space completing itself in periods immeasurable by human thought, is, so far as we can see, universal and eternal--each alternating phase of the process predominating now in this region of space and now in that, as local conditions determine. 15. All these phenomena, from their great features down to their minutest details, are necessary results of the persistence of force under its forms of matter and motion. Given these as distributed through space, and their quantities being unchangeable, either by increase or decrease, there inevitably result the continuous redistributions distinguishable as evolution and dissolution, as well as all these special traits above enumerated. 16. That which persists unchanging in quantity, but ever changing in form, under these sensible appearances which the universe presents to us, transcends human knowledge and conception--is an unknown and unknowable power, which we are obliged to recognise as without limit in space and without beginning or end in time. All that is comprised in the dozen volumes which, exclusive of the minor works and the Sociological Tables, form the great body of the Synthetic Philosophy, is the expansion of this abstract. The general lines laid down in that Philosophy have become a permanent way along which investigation will continue to travel. The revisions which may be called for will not affect it fundamentally, being limited to details, more especially in the settlement of the relative functions of individuals and communities, and cognate questions. Into these we cannot enter here. Suffice it, that to those who have the rare possession of sound mental peptics, no more nutritive diet can be recommended than is supplied by First Principles and the works in which its theses are developed. For those who, blessed with good digestion, lack leisure, there is provided in a convenient volume the excellent epitome which Mr. Howard Collins has prepared.