We may not measure except with a fifty cubit rope, neither shorter nor longer. One may not measure except [with the rope] opposite his heart. If he was measuring and reached a valley or a mound, he should span it and return to his measuring; if he reached a mountain, he should span it and return to his measuring; provided he does not go out of the techum. If he is unable to span it — regarding this R’ Dostai bar R’ Yannai stated in R’ Meir’s name: I have heard that we pierce mountains.

We may not [accept] measure[ments] except from an expert. If he extended [the techum] at one point and shortened it at another, the extended [techum] is followed. If one extended [it] while another shortened [it], the one who extended [it] is followed. Even a male slave, even a female slave is believed to say, ‘Until here is the Sabbath techum.’’ For the Sages did not state this law to be stringent but rather to be lenient.

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].

One who lives together with a gentile in a [single] courtyard, or with one who does not accept [the laws of] eruv, that person places a restriction upon him — [these are] the words of R’ Meir. R’ Eliezer ben Yaakov says: He never restricts, unless there are two Jews restricting each other.

Rabban Gamliel said: It once happened that a Sadducee lived with us in an alley in Jerusalem, and Father told us: ‘‘Hurry and carry out all your utensils into the alley before he carries out and restricts you.’’ R’ Yehudah related [this] in different terms: ‘‘Hurry and attend to your needs in the alley before it passes and he restricts you.’’

The residents of a courtyard, one of whom forgot to participate in the eruv, his house is restricted with regard to carrying in and carrying out, to him and to them; but theirs are permitted to him and to them. If they ceded their rights to him, he is permitted, but they are restricted. If there were two, they restrict each other; because an individual can cede rights and acquire rights, two can cede rights but cannot acquire rights.

When may rights be ceded? Beis Shammai say: While it is yet day. But Beis Hillel say: When it is dark. One who ceded his rights then carried out, whether unintentionally or deliberately, restricts — [these are] the words of R’ Meir. R’ Yehudah says: Deliberately, he restricts; unintentionally, he does not restrict.

If a houseowner was a partner with neighbors, with this one in wine and with that one in wine, they need not make an eruv; with this one in wine and with that one in oil, they must make an eruv. R’ Shimon says: In either case they need not make an eruv.

If five groups spent the Sabbath in one mansion — Beis Shammai say: An eruv for each group. But Beis Hillel say: One eruv for all of them. They agree, however, that when some of them are quartered in rooms or upper stories, they need an eruv for each group.

Brothers or partners who eat at their father’s table, but who sleep in their own homes, need an eruv for each one. Therefore, if one of them forgot to contribute to the eruv, he must nullify his rights. When is this so? When they bring their eruv to another place; but if the eruv was brought to them, or there are no other residents in the courtyard, they need not contribute to the eruv.

Five courtyards which open one into the other and into an alley — if they made an eruv in the courtyards but did not make a shituf in the alley, they are permitted in the courtyards but prohibited in the alley; if they did make a shituf in the alley, they are permitted here and there. If they made an eruv for the courtyards and a shituf for the alley, but one of the residents of the courtyard forgot to contribute to the eruv, they are permitted here and there; if one of the residents of the alley did not participate in the shituf, they are permitted in the courtyards, but are prohibited in the alley; for an alley is to the courtyards as a courtyard is to the houses.