Page:Popular Science Monthly Volume 3.djvu/425

Rh or shorter time, a dash or a dot is produced at the station to which the signal is sent. The dash and dot are combined in different ways to indicate the different letters, as shown in the following scheme, which is now generally adopted both in Europe and America:

A space about equal to the length of a dash is left between two letters and a space of about twice this length between two words.

In needle-telegraphs, the dot is represented by a deflection to the left, and the dash by a deflection to the right.

Fig. 12 represents Morse's indicator in connection with what is



called a relay; that is to say, an apparatus which, on receiving a feeble current from a distance, sends on a much stronger current from a battery on the spot. The key (B) being up, a current arriving by the line-wire passes through the key from c to a, thence through another