The property at Twickenham is properly described by Roscoe as lying on both sides of the highway, rendering it necessary for him to cross the road to arrive at the higher and more ornamental part of his gardens. In order to obviate this inconvenience, he had recourse to the expedient of excavating a passage under the road from one part of his grounds to the other, a fact to which he alludes in these lines: "Know all the toil the heavy world can heap Rolls o'er my grotto, nor disturbs my sleep." The lower part of these grounds, in which his house stood, constituted, in fact, only the sloping bank of the river, by much the smaller portion of his territory. The passage, therefore, was very necessary to that far greater part, which was his wilderness, shrubbery, forest, and every thing, where he chiefly planted and worked. This passage he formed into a grotto, having a front of rude stone-work opposite to the river, and decorated within with spars, ores, and shells. Of this place he has himself left this description: "I have put the last hand to my works of this kind, in happily finishing the subterranean way and grotto. I found there a spring of the clearest water, which falls in a perpetual rill, that echoes through the cavern night and day. From the River Thames you see through my arch, up a walk of the wilderness, to a kind of open temple wholly composed of shells in the rustic manner; and from that distance under the temple, you look down through a sloping arcade of trees, and see the sails on the river passing suddenly and vanishing, as through a perspective glass. When you shut the door of this grotto, it becomes on the instant, from a luminous room, a _camera obscura_, on the walls of which all the objects of the river, hills, woods, and boats are forming a moving picture, in their visible radiations; and when you have a mind to light it less, it affords you a very different scene. It is finished with shells, interspersed with looking-glass in regular forms, and in the ceiling is a star of the same material, at which, when a lamp of an orbicular figure of thin alabaster is hung in the middle, a thousand pointed rays glitter, and are reflected over the place. There are connected to this grotto, by a narrow passage, two porches, one toward the river, of smooth stones, full of light and open; the other toward the garden, shadowed with trees, rough with shells, flints, and iron ore. The bottom is paved with simple pebbles, as is also the adjoining walk up the wilderness to the temple, in the natural taste, agreeing not ill with the little dripping murmur, and the aquatic idea of the whole place. It wants nothing to complete it but a good statue with an inscription, like that beautiful antique one which you know I am so fond of. You will think I have been very poetical in this description; but it is pretty near the truth." To this prose description Pope added this one in verse: