What does Archimedes' Principle state?

The Archimede's principle states that when an object is immersed under a body of water the amount of water rose from its initial level is the amount of matter in the object immersed.

For example, a graduated cylinder was filled with 25 cm3 of water, then pebble was put inside the cylinder - the water rose and became 35 cm3. the difference between the final volume and the initial volume is the volume of that pebble. And it is 10.