The friction

Phileas Fogg lived alone,and so to speak, outside of every social relation; and as he knew that in this world account must be taken of friction, and that friction retards, he never rubbed against anybody.

The friction is the force that opposes free sliding between two surfaces materials,the one on the other.
The friction is important has many applications:
-Rail adhesion: the friction between a steel wheel and a steel rail.

-Road slipperiness or skid resistance due to snow,ice,water,loose material and the road surface on the traction produced by the wheels of a vehicle.

-the friction in the brakes of a vehicle( car, van, truck,moped, motorcycle):

the friction between the pads and the disc makes the wheel stops

The study of friction we can make it back to earlier periods as in 37-41 d.c when the king Caligola built large ships for for ceremonial celebrations or parties.
We are talking about the Ship of lake Nemi, brought to the surface by  Guido Ucelli in the 1928.

first ship

second ship

In the picture shows the ships found in the lake, in the second vessel were Rovate the curious balls bronze.
These spheres were assembled with the other pieces and form an object that turned the sliding friction to rolling.

bronze balls to reduce friction 1928-1929

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