The rod was bent in the middle so that it could be turned as with a crank.
Each rod therefore contains on two of its faces multiples of digits which are complementary to those on the other two faces; and the multiples of a digit and of its complement are reversed in position.
The cylinder contains towards n a sliding rod, and towards 0 a compressed spiral spring.
I do not remember what they all were; but I do know that mother, father, sister, teacher were among them--words that were to make the world blossom for me, "like Aaron's rod, with flowers."
In 1831 Wheatstone by his " magic lyre" experiment showed that, when the sounding-boards of two musical instruments are connected together by a rod of pine wood, a tune played on one will be faithfully reproduced by the other.
