was utilised in his type-printing telegraph, patented in 1841. This was
the first apparatus which printed a telegram in type. It was worked by
two circuits, and as the type revolved a hammer, actuated by the
current, pressed the required letter on the paper. in 1840 Wheatstone
also brought out his magneto-electrical machine for generating
continuous currents, and his chronoscope, for measuring minute intervals
of time, which was used in determining the speed of a bullet or the
passage of a star. In this apparatus an electric current actuated an
electro-magnet, which noted the instant of an occurrence by means of a
pencil on a moving paper. It is said to have been capable of
distinguishing 1/7300 part of a second, and the time a body took to fall
from a height of one inch.

The same year he was awarded the Royal Medal of the Royal Society for
his explanation of binocular vision, a research which led him to
construct the stereoscope. He showed that our impression of solidity is
gained by the combination in the mind of two separate pictures of an
object taken by both of our eyes from different points of view. Thus,
in the stereoscope, an arrangement of lenses and mirrors, two
photographs of the same object taken from different points are so
combined as to make the object stand out with a solid aspect. Sir David
Brewster improved the stereoscope by dispensing with the mirrors, and
bringing it into its existing form.

The 'pseudoscope' (Wheatstone was partial to exotic forms of speech) was
introduced by its professor in 1850, and is in some sort the reverse of
the stereoscope, since it causes a solid object to seem hollow, and a
nearer one to be farther off; thus, a bust appears to be a mask, and a
tree growing outside of a window looks as if it were growing inside the
room.