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 stonework 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 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