If, for example, you take pure steel as one of the most solid metal bodies of all metals, break such a steel bar in two, you will easily recognize the crystalline structure at the white fracture, which will appear to the unaided eye to be strikingly uniform; but observed with a microscope, this fracture surface will get an appearance like the sight of one discovering all kinds of larger and smaller elevations from a high mountain below. But if such a difference can be perceived in the crystalline structure of one of the most solid metal bodies, how much greater is such a difference with those far less solid bodies, whose crystalline structure is often easily perceptible to the naked eye between large and small, dense and less dense; and it is therefore all the more perfectly true that the center of gravity and the center of the body-measure can never coincide. – The Earth, Chapter 1, Paragraph 4