had brought it to such perfection that it would be affected by a
variation of one-tenth of one second in the aggregate speed of ten
revolutions, and an increase or decrease of a tenth of a grain in the
weight of the volume of the compressed air. It was so sensitive that
John Henry and Newton trod cautiously on the floor of the workshop so as
not to set it vibrating under the glass clock-shade, where it was kept
safe from dust and dampness.

After it had been placed there to wait for the casting, the inventor
took the engine to pieces and made the small changes that would be
necessary before finally putting it together again, which would probably
occupy two days.

Meanwhile the little City of Hope grew rapidly, and was becoming an
important centre of civilisation and commerce, though it was only made
of paper and chips, and bits of matchboxes and odds and ends cleverly
put together with glue and painted; except the people in the street. For
it was inhabited now, and though the men and women did not move about,
they looked as if they might, if they were only bigger. Overholt had
seen the population in the window of a German toy-shop one day when he
was in New York to get a new crocusing wheel for polishing some of the
small parts of the engine. They were the smallest doll-people he had
ever seen, and were packed by dozens and dozens in Nuremberg toy-boxes,
and cost very little, so he bought a quantity of them. At first Newton
rather resented them, just because they were only toys, but his father
explained to him that models of human figures were almost necessary to
models of buildings, to give an idea of the population, and that when
architects make coloured sketches of projected houses, they generally
draw in one or two people for that reason; and this was perfectly
satisfactory to the boy, and saved his dignity from the slight it would