why are pool balls smaller than billiard balls?

[OTLB]

also please make comments in the mech section under
another post:

http://forums.azbilliards.com/showthread.php?t=140841

 

[3andstop]

I don't know why pool balls are smaller, but I think billiard balls are bigger because the inertia they hold based on their extra weight allows then to continue their roll better.

 

[TimurA]

May one of the reasons ,why billiard balls are bigger,be to make the game simpler?

I tried pool balls on carom table to see what happens.I am not a good player, but with pool balls, even the positions in which the second object in the corner is difficult let alone other positions in which the second object ball is very small.To find a smaller second object ball to score is much more difficult.