d, the
streets were decorated, and the city was illuminated at night.
The festivities rose to the highest pitch in September with Field
receiving the plaudits of all New York. Special services were held in
Trinity Church, and a great celebration was held in Crystal Palace.
The mayor presented to Field a golden casket, and the ceremony was
followed by a torchlight parade. That very day the last message went
over the wire.

The shock to the public was tremendous. Many insisted that the cable
had never been operated and that the entire affair was a hoax. This
was quickly disproved. Aside from the messages between Queen and
President many news messages had gone over the cable and it had proved
of great value to the British Government. The Indian mutiny had been
in progress and regiments in Canada had received orders by mail to
sail for India. News reached England that the mutiny was at an end,
and the cable enabled the Government to countermand the orders, thus
saving a quarter of a million dollars that would have been expended in
transporting the troops.

The engineers to whom the operations of the cable had been intrusted
had decided that very high voltages were necessary to its successful
operation. They had accordingly installed huge induction coils and
sent currents of two thousand volts over the line. Even this voltage
had failed to operate the Morse instruments, the drag by induction
proving too great. The strain of this high voltage had a very serious
effect upon the insulation. Abandoning the Morse instruments and
the high voltage, recourse was then had to Professor Thomson's
instruments, which proved entirely effective with ordinary battery
current.

Because of the effect of induction the current is much delayed
in traveling through a long submarine cable and arrives in waves.
Professor Thomson devised his mirror galvanometer to meet this
difficulty. This device consists of a large coil of very fine wire, in
the center of which, in a small air-chamber, is a tiny mirror. Mounted
on the back of the mirror are very small magnets. The mirror is
suspended by a fiber of the finest silk. Thus the weakest of currents
coming in over the wire serve to deflect the mirror, and a beam
of light being directed upon the mirror and reflected by it upon a
screen, the slightest movement of the mirror is made visible. If the
mirror swings too far its action is deadened by compressing the air in
the chamber. The instrument is one