the children to help you poise seven in one plane above
the three; then let another child place three more above
the seven, and you have the CORE of the MOON
completely. If you want a more poetical illustration, it
was what Mr. Wordsworth calls a mass

"Of conglobated bubbles undissolved."


Any section through any diameter looked like an
immense rose-window, of six circles grouped round a
seventh. In truth, each of these sections would reveal
the existence of seven chambers in the moon,--each a
sphere itself,--whose arches gave solidity to the whole;
while yet, of the whole moon, the greater part was air.
In all there were thirteen of these moonlets, if I am so
to call them; though no one section, of course, would
reveal so many. Sustained on each side by their groined
arches, the surface of the whole moon was built over
them and under them,--simply two domes connected at the
bases. The chambers themselves were made lighter by
leaving large, round windows or open circles in the parts
of their vaults farthest from their points of contact, so
that each of them looked not unlike the outer sphere of
a Japanese ivory nest of concentric balls. You see
the object was to make a moon, which, when left to its
own gravity, should be fitly supported or braced within.
Dear George was sure that, by this constant repetition of
arches, we should with the least weight unite the
greatest strength. I believe it still, and experience