If a town of an individual became public property, we may make an eruv for its entirety; but if a public [town] became an individual’s, we may not make an eruv for its entirety, unless we exclude [an area] from it equivalent to the town of Chadashah in Judea, which has fifty inhabitants — [these are] the words of R’ Yehudah. R’ Shimon says: Three courtyards containing two dwellings.

One who was to the east and had told his son, ‘‘Make an eruv for me in the west’’; to the west and had told his son, ‘‘Make an eruv for me in the east’’ — if the distance from him to his house is two thousand cubits and to his eruv more than that, he is permitted [the techum of] his house but forbidden [the techum of] his eruv; if to his eruv is two thousand cubits and to his house more than that, he is forbidden [the techum of] his house but permitted [the techum of] his eruv. One who places his eruv in the extension of a town has accomplished nothing. If he placed it beyond the techum, even one cubit, whatever he gains he loses.

The residents of a large town may traverse an entire small town, but the residents of a small town may not traverse an entire large town. How so? One who was in a large town and placed his eruv in a small town, [or] in a small town and placed his eruv in a large town, may traverse its entirety and two thousand cubits beyond it. But R’ Akiva says: He has no more than two thousand cubits from the place of his eruv.

R’ Akiva said to them: Do you not agree with me regarding one who placed his eruv in a cave, that he has no more than two thousand cubits? They answered him: ‘‘When is this so? Only when there are no inhabitants in it; but if it had inhabitants in it, he may traverse its entirety and beyond it for two thousand cubits.’’ Thus it follows that its interior is more lenient than its roof. And concerning the surveyor, about whom they said, ‘‘We give him two thou-sand cubits,’’ even if his measurement ended in the middle of a cave [it is so].