was
established. Almost the first news that came over the wire was that of
the signing of the treaty of peace which ended the war between Prussia
and Austria.

Early in August the _Great Eastern_ again steamed away to search for
the cable broken the year before. Arriving on the spot, the grapples
were thrown out and the tedious work of dragging the sea-bottom was
begun. After many efforts the cable was finally secured and raised to
the surface. A new section was spliced on and the ship again turned
toward America. On September 7th the second cable was successfully
landed, and two wires were now in operation between the continents.
Thus was the great task doubly fulfilled. Once again there were public
celebrations in England and America. Field received the deserved
plaudits of his countrymen and Thomson was knighted in recognition of
his achievements.

[Illustration: THE "GREAT EASTERN" LAYING THE ATLANTIC CABLE. 1866]

The new cables proved a success and were kept in operation for many
years. Thomson's mirror receiver had been improved until it displayed
remarkable sensitiveness. Using the current from a battery placed in
a lady's thimble, a message was sent across the Atlantic through one
cable and back through the other. Professor Thomson was to give to
submarine telegraphy an even more remarkable instrument. The mirror
instrument did not give a permanent record of the messages. The
problem of devising a means of recording the messages delicate enough
so that it could be operated with rapidity by the faint currents
coming over a long cable was extremely difficult. But Thomson solved
it with his siphon recorder. In this a small coil is suspended between
the poles of a large magnet; the coil being free to turn upon its
axis. When the current from the cable passes through the coil it
moves, and so varies the position of the ink-siphon which is attached
to it. The friction of a pen on paper would have proved too great a
drag on so delicate an instrument, and so a tiny jet of ink from the
siphon was substituted. The ink is made to pass through the siphon
with sufficient force to mark down the message by a delightfully
ingenious method. Thomson simply arranged to electrify the ink, and
it rushes through the tiny opening on to the paper just as lightning
leaps from cloud to earth.

Professor, now Sir, Thomson continued to take an active part in the
work of designing and laying new cables. Not only did he contribute
th