Mark Isambard Brunel, the great engineer, was standing one
day, about three-quarters of a century ago, in a ship-yard
watching the movements of an animal known as the _Teredo
navales_--in English, the naval wood-worm--when a brilliant
thought suddenly occurred to him. He saw that this creature
bored its way into the piece of wood upon which it was operating
by means of a very extraordinary mechanical apparatus. Looking
at the animal attentively through a microscope, he found that it
was covered in front with a pair of valvular shells; that with
its foot as a purchase, it communicated a rotary motion and a
forward impulse to the valves, which, acting upon the wood like
a gimlet, penetrated its substance; and that as the particles of
wood were loosened, they passed through a fissure in the foot
and thence through the body of the borer to its mouth, where
they were expelled. “Here,” said Brunel to himself, “is the
sort of thing I want. Can I reproduce it in artificial form?”
He forthwith set to work, and the final result of his labors,
after many failures, was the famous boring-shield with which
the Thames tunnel was excavated. This story was told by Brunel
himself, and there is no reason to doubt its truth. The keen
observer can draw useful lessons from the humblest of the works
of God.--New York _Ledger_.
(1632)