711. Dividing a Pit

Shabbos 14:22

If a person throws a mat from a public domain into a pit ten handbreadths deep and eight handbreadths wide (about 30”x24”) and it divides the width of the pit in half, he is not liable because when the mat lands, it nullifies the domain, each of the resulting halves being smaller than four handbreadths by four handbreadths (1’x1’).

Shabbos 14:23

If a person throws an object into a pit in the public domain that is ten handbreadths deep, four handbreadths by four handbreadths, and filled with water, he is liable even if the article lands on the surface of the water. This is because being filled with water does not nullify the status of a domain. If the pit were filled with produce (for example), one who throws something into it would not be liable because the produce (or whatever) would reduce the size of the pit.