Yerushalmi Eruvin 10:7 ירושלמי עירובין י׳:ז׳

MISHNAH: If the railing around a cistern in the public domain is ten hand-breadths high, one may fill from it through a window above it on the Sabbath¹⁷Since the space within the enclosure is private domain and the airspace above 10 hand-breadths from the ground is exempt space, it is possible to use one private domain while standing in another private domain if the connection is through exempt space.. If a dungheap in the public domain is ten hand-breadths high, one may pour waste water onto it through a window above it on the Sabbath.

HALAKHAH: Paragraph¹⁰⁶Discussion of Mishnah 6.. Does one not consider depth equal to height¹⁰⁷Since a cistern usually is deeper than 10 hand-breadths (a premiss disputed by the Babli 99b), it defines a private domain whether or not it has a railing around. Why does the Mishnah insist on a railing?? If its mouth is not wide four [hand-breadths]¹⁰⁸If the opening does not contain a square of 4-by-4 hand-breadths it cannot define a domain by itself unless it is walled in by a wall at least 10 hand-breadths high.. So far if it is blocked in. If it is far away¹⁰⁹The cistern is close to the house; even though it is in the public domain its status is karmelit. If it is farther away from the house to be genuine public domain, it needs some action to make it usable from a private domain (disputed by the Babli 99b).? Rav and Samuel; one said one puts in a plank; the other said, one plants a stick¹¹⁰The first opinion requires only a token separation, the second a genuine partition, even if hanging from the balcony, of 10 hand-breadths width.. We did not know who said what. Since Samuel stated, higher than ten [hand-breadths]is rabbinically forbidden¹¹¹He holds that biblically exempt space still is rabbinically forbidden. Therefore he must need a genuine partition to allow water to be drawn through what otherwise would be exempt space., he is the one who said that one puts in a plank.

If they were two¹¹²If a cistern was in the public domain and two houses on opposite sides could use its water on the Sabbath.. Two Amoraim, one said ten [hand-breadths], the other one said four¹¹³Following Rav, who in the case of a single house requires only a token partition, does one need a plank of fully 10 hand-breadths in the case of two houses or is a width of 4 hand-breadths sufficient? The numerals all are in the masculine.. He who said ten objected to the one saying four: Does it not turn out that two domains use one domain? He told him, the public domain annuls¹¹⁴Since the plank is hanging down, the water is drawn through exempt space, which for him is unquestionably permitted. It only is exempt space which uses the cistern below, and this is permitted..