d. Barges and rafts usually employ tidal motion only.

e. Rowing boats, &c., hand power paddle and screw boats, horse towage.

In air, balloons are propelled by:

a.

Wind, acting on the inflated balloon, or on an umbrella-shaped or other sail; also on the under side of inclined planes of large area.

b.

Balloons of elongated form have been propelled by an engine placed in the car, driving either a large screw propeller or wings.

c.

Various attempts have been made to work flying machines (generally having some form of wings) by the power of a man’s hands and feet, with very little success.

a. Wind, acting on the inflated balloon, or on an umbrella-shaped or other sail; also on the under side of inclined planes of large area.