"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 sleeping 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 state, 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."