William Kingdon Clifford, answered from the texts and cited to the page.
Small portions of space are analogous to little hills on a surface which is on the average flat; the property of being curved is continually passed on from one portion of space to another after the manner of a wave; and this variation of the curvature of space is what really happens in the phenomenon we call the motion of matter.1234
There are three kinds of variation in the curvature of our space which we ought to consider as within the range of possibility.The Common Sense of the Exact Sciences, pp. 224–225
These variations of the icurvature with the time may produce effects which we not unnaturally attribute to physical causes indepen dent of the geometry of our space. We might even ^-o so far as to assign to this variation of the curvature <>l what really happens in that phenomenon which |space |we term the motion of matter.The Common Sense of the Exact Sciences, pp. 226–227
What lesson may we learn by analogy for the threedimensioned space in which we ourselves exist? To begin with, we assume that all our space is perfectly same, or that solid figures do not change their shape in passing from one position in it to another. We base this postulate of sameness upon the results of observation n that somewhat limited portion of space of which we are cognisant.The Common Sense of the Exact Sciences, pp. 223–224
Yet geometrical constructions can be made with extreme accuracy upon such a surface, on the supposition that it is an exact plane. If, therefore, the sharp points, edges, and furrows of space are only small enough, there will be nothing to hinder our conviction of its elementary flatness.Lectures and Essays Vol I, ed. Pollock with memoir
Two paragraphs with no mathematics, cited ever since as an anticipation of general relativity.