"The great weight of the ship may indeed prevent her from acquiring her greatest velocity; but when she has attained it, she will advance by her own intrinsic motion, without gaining any new degree of velocity, or lessening what she has acquired"

This quote by William Falconer is describing the idea of inertia. Inertia is the propensity of a challenge remain at rest or in movement unless acted upon by an external force. In this quote, Falconer is stating that the fantastic weight of a ship might prevent it from reaching its optimum velocity, but once it has actually reached that speed, it will continue to move at that very same speed without gaining or losing any speed. This is due to the fact that the ship has actually gotten its own momentum and is now subject to the law of inertia. This quote is a suggestion that once an item has acquired its own momentum, it will continue to move at the exact same speed unless acted upon by an external force. This idea is very important to understand when it pertains to the movement of items in the real world.