All of the greatest commercial aids require some care, such, for
instance, as the telephone, typewriter, adding machine, duplicating
machine and so on.
[Illustration: Bearing Repeater Equipped with Windows in Storm Cover.]
The magnetic compasses aboard ship receive especially watchful
attention, to see that they are not meddled or tampered with. As a rule
the entire ship’s crew, including the youngest apprentice, knows that
the compass must in no way be handled.
It should be remembered that the Sperry Gyro-Compass is a mechanical
compass. Although the very best materials, design and skill enter
into its construction, it is still liable to failure. Even with that
possibility, it is so superior to the magnetic compass that it more
than justifies its installation use. In the same way the electric
light, although liable to failure, is vastly superior to the old oil
lamp. The oil lamps are seldom used, yet they are carried aboard ships
for the contingency which might happen. Similarly a failure of the
electric or hydraulic steering gear may necessitate the temporary use
of the inefficient hand-steering gear.
[Illustration: In Venice, graceful Gondolas take the place of cabs.]
[Illustration: Fig. 33. Repeater at After Steering Station.
Fig. 35. Repeater on Wing of Upper Bridge.