The lessees of the Eddystone, in those days, seem to have been liberal-minded people. The tolls ceased with the extinction of the light, and could not be renewed until it was again exhibited. It was their apparent interest, therefore, to get a structure run up on the old model as quickly as possible. It was true it had been destroyed by fire, but a little modification of the old arrangements would probably have prevented such a calamity recurring, and it had proved itself stable and seaworthy. Nevertheless, they not only consulted the ablest engineer of the day, but submitted to the delay and extra cost involved in the adoption of his advice to build of stone and granite. The point of most enduring interest connected with the present Eddystone is the peculiarity of its form, which is familiar, probably, to everybody in the kingdom, from the child, who has seen it in a magic-lantern, to the civil engineer who knows Smeaton’s stately folio by heart. Until he built so, the form was almost unknown to us; and since he built so, all the ocean lighthouses have been modifications of it. It is interesting to contrast the reasoning of Mr. Alan Stevenson, the builder of the “Skerryvore,” another of these deep-sea lamp-posts, as they have been called, off the western coast of Scotland,--with the _instincts_ of Smeaton, so to speak, on the same subject. It may not be very edifying to the general reader to learn “that, as the stability of a sea-tower depends, _cæteris paribus_, on the lowness of its centre of gravity, the general notion of its form is that of a cone; but that, as the forces to which its several horizontal sections are opposed decrease towards its top in a rapid ratio, the solid should be generated by the revolution of some curve line convex to the axis of the tower, and gradually approaching to parallelism with it; and that this, in fact, is a general description of the Eddystone Tower, devised by Smeaton.” Neither is it a thing likely to be remembered, without saying it over a good many times to oneself, that “the shaft of the Skerryvore pillar is a solid, generated by the revolution of a rectangular hyperbola about its asymptote as a vertical axis.” But if we understand the respective narratives of the constructors rightly, Smeaton worked from analogy, and Stevenson from mathematical calculation. Smeaton tells us of his desire to make his lighthouse resemble the trunk of a stately tree, and he gives drawings both of a trunk and of a branch, to show how they start, the one from the ground, and the other from the main stem. He is also constantly recurring to the idea of the elasticity of stone, and he quotes a report from one of the keepers, that on one occasion “the house did shake as if a man had been up in a great tree.” Certainly, the effect to the eye in looking at the Eddystone, corroborates the conception with which his mind was evidently possessed; it emerges from the sea; the curve of the natural