Siman - Eruvin Daf 59

• Making a shituf in a public city that became private

In general, the Rabbanon were concerned that in public towns, if one shituf permitted carrying in the entire town, then people, particularly the children, might come to think that carrying in any public domain is permitted, forgetting that there was a shituf. To prevent forgetting about the prohibition of carrying, they mandated that one section of the city is not included in the shituf so that carrying will be forbidden between the town and the excluded area.

With this background, the next Mishnah states, עיר של יחיד ונעשית של רבים – If a private town became public, מערבין את כולה – we may join the entire town in one eruv, ושל רבים ונעשית של יחיד – but if a public town became private, אין מערבין את כולה – we may not join the entire town in one eruv, unless one set aside outside the eruv an area that is equivalent in size to the town of Chadashah in Yehudah which has fifty inhabitants, according to Rebbe Yehudah. Rebbe Shimon says that it is sufficient to set aside three chatzeiros containing at least two dwellings each. Rashi explains that in a case of a public city that became private, there is a concern that the city will become public again, and joined in one shituf, and people will come to forget about the prohibition of carrying.

• Adjusting a reshus harabim that runs through the middle of town

It was taught in a Baraisa that if a private town became public and a reshus harabim passes through the middle of the town,או קורה מכאן וקורה מכאן עושה לחי מכאן ולחי מכאן  - one places either a lechi at both ends or a korah at both ends, ונושא ונותן באמצע – and then one may carry in the street in between them.

The Gemara asks who the Tanna of the Baraisa is, and Rav Huna brei d’Rav Yehoshua answers that it is Rebbe Yehudah, who holds that a reshus harabim that has two walls is a reshus hayachid which can be adjusted with either two lechis or two korahs.

• The status of a ladder against the wall of a thoroughfare

Rav Ami bar Ada of Harpanah asked Rabbah, סולם מכאן ופתח מכאן מהו – If a public town had a ladder at one end of the thoroughfares that enabled people to walk over the wall, and a regular entrance at the other, what is the law? Do we consider the thoroughfare as if it has two entrances and therefore one section of the city must be left out of the shituf, or is it considered a town with one entrance and the entire town is included in the shituf?

Rabbah said in the name of Rav, סולם תורת פתח עליו – the ladder has the status of an entrance, thereby prohibiting one shituf for the entire town. Rav Nachman said that Rabbah misunderstood Rav and that Rav Adda said in the name of Rav, סולם תורת פתח עליו ותורת מחיצה עליו – A ladder has the status of an entrance and of a mechitzah. It has the status of a mechitzah so that it does not cancel the town’s wall, thereby permitting one shituf for the entire town. It is considered an entrance when it is between two chatzeiros, giving the residents the choice to either make an eruv between themselves, or two make two separate eruvin.