referred to in Rule 39) is legally caught by a Fielder, such ball is
legally held by a Fielder on the base occupied by the Base Runner when
such ball was struck (or the Base Runner be touches with the ball in the
hands of a Fielder), before he retouches said base after such Fair or
Foul Hit ball was so caught: _Provided_, that the Base Runner shall not
be out in such case, if, after the ball was legally caught as above, it
be delivered to the bat by the Pitcher before the Fielder holds it on
said base, or touches the Base Runner with it; but if the Base Runner in
attempting to reach a base, detaches it before being touched or forced
out, he shall be declared safe.