384 THE OCEAN. 
merchandise between continents isles and nations, 
the other carries the no less precious, but impond- 
erable, wealth of messages from land to land. 
The first attempt to lay the cable, in the year 
1857,was a failure, because the wire parted and 
the vessel returned with a sorrowful but not dis- 
heartened company. The next effort was the 
following year, with a stronger cable and better 
machinery for “paying ” it out. The cable was 
seven strands of wire made into a rope and covered 
with several thicknesses of substances designed to 
keep the water from reaching the metallic wires 
which conducted the electricity. When finished it 
weighed nearly two thousand pounds to the mile 
in length and was so strong that six miles of it 
could be drawn straight in water. The number 
of cables will increase as fast as needed. 
In 1873 there were three in full operation, and 
they probably will last many years. It requires 
but a small quantity of electricity to operate them. 
The signals used in ocean telegraphy differ from 
those used for land lines. On the French line 
small flashes of light are reflected on a mirror 
and serve the purpose. The small amount of elec- 
tricity used on long cables obviates the danger of 
injury to the wires, by an overcharge. Science 
has also enabled the electrician, in case of a break 
in the wire, to tell almost its exact place,to which 
a vessel can be sent to make repairs. Thus it is 
that the ocean is subjected to man’s dominion day 
by day. 
THE END. 
