What is "internal navigation"

Navigation \Nav`i*ga"tion\, n. [L. navigatio: cf. F. navigation.]

1. The act of navigating; the act of passing on water in ships or other vessels; the state of being navigable.

2. 1. The science or art of conducting ships or vessels from one place to another, including, more especially, the method of determining a ship's position, course, distance passed over, etc., on the surface of the globe, by the principles of geometry and astronomy.

   2. The management of sails, rudder, etc.; the mechanics of traveling by water; seamanship.

3. Ships in general. [Poetic]
   --Shak.

   A["e]rial navigation, the act or art of sailing or floating in the air, as by means of airplanes or ballons; aviation; a["e]ronautic.

   Inland navigation, Internal navigation, navigation on rivers, inland lakes, etc.