(Mishnah - R. Meir): If one left his house and went to another city, he forbids, whether he is a Yisrael or Nochri.

R. Yehudah says, he does not forbid;

R. Yosi says, a Nochri forbids, but a Yisrael does not, for he is unlikely to return on Shabbos.

R. Shimon says, even if he left his house to spend Shabbos with his daughter in the same city, he does not forbid, for he does not plan to return.

(Gemara): The reason for R. Meir, is that R. Meir says that a locked house (the owner went away for Shabbos) forbids, for he can come through an Eruv, or he might transgress and come.

(Mar Ukvan citing Rav): The Halachah follows R. Meir.

(Mishnah): If there is a pit [on the boundary] between two Chatzeros, neither may draw water from it unless there is a 10 Tefachim Mechitzah. It can be below (this will be explained) or inside the brim [of the pit];

R. Shimon ben Gamliel says, Beis Shamai say, the Mechitzah [must be] below. Beis Hillel say [it may be] above;

R. Yehudah says, the Mechitzah is no better than the wall between the Chatzeros! (The wall itself permits.)

(Gemara - R. Yakov citing R. Yehoshua ben Levi): The wall must be submerged in the water the full [height] of the bucket.

The words of [the following] Rabanan disagree;

(R. Tavlai citing Rav): The law of a ruin (a hanging wall does not permit it) does not apply to water. (Here, a hanging wall permits. It need not touch the water.)

If there was a roof [over the pit], you view it as if it descends and seals (no wall is needed). If there were thick beams [inserted in the wall, over the pit], you view them as if they descend and seal.

Question: (Sometimes the bucket will go to the other side.) Does it not turn out that two Reshuyos use one Reshus?!

Answer: [Chachamim] gauged that a bucket does not go more than four Tefachim (it will not go to the other side. We explained this like SHA'AREI TORAS ERETZ YISRAEL.)

Contradiction: R. Yehudah contradicts himself!

There, R. Yudan exempts water (from Shevisah, so one may take it wherever he may go), for it is has no significance, and here he says so (that some wall is needed to permit it)!

(Rav Huna): [Beis Hillel permit the Mechitzah to be above the water, but] the Mechitzah must protrude into the cavity of the pit.