Halacha

הלכה א
עוֹמֵד אָדָם בִּרְשׁוּת הָרַבִּים וּמְטַלְטֵל בִּרְשׁוּת הַיָּחִיד כֻּלָּהּ. וְעוֹמֵד בִּרְשׁוּת הַיָּחִיד וּמִטַּלְטֵל בִּרְשׁוּת הָרַבִּים וּבִלְבַד שֶׁלֹּא יוֹצִיא חוּץ לְאַרְבָּעָה אַמּוֹת. וְאִם הוֹצִיא פָּטוּר מִפְּנֵי שֶׁהוּא בִּרְשׁוּת אַחֶרֶת. וְכֵן עוֹמֵד אָדָם בִּרְשׁוּת הַיָּחִיד וּפוֹתֵחַ בִּרְשׁוּת הָרַבִּים, בִּרְשׁוּת הָרַבִּים וּפוֹתֵחַ בִּרְשׁוּת הַיָּחִיד. בְּהֵמָה שֶׁהָיְתָה רֻבָּהּ בַּחוּץ וְרֹאשָׁהּ בִּפְנִים אוֹבְסִין אוֹתָהּ. וּבְגָמָל עַד שֶׁיְּהֵא רֹאשׁוֹ וְרֻבּוֹ בִּפְנִים הוֹאִיל וְצַוָּארוֹ אָרֹךְ:
כסף משנה
1.
A person standing in a public domain may move [articles] throughout a private domain. Similarly, a person standing in a private domain may move [articles] within a public domain, provided he does not transfer them beyond four cubits.1In both these instances, there is not even a Rabbinic prohibition against moving the articles. As mentioned in the notes on the following halachah, Rashi and the Rashba state that this leniency applies only with regard to articles the person does not require in the domain in which he is standing. If he needs them, the Rabbis decreed that they may not be moved, lest the person forget and bring the articles into the domain where he is standing. The Shulchan Aruch (Orach Chayim 350:1) appears to favor the view of these authorities. If he transfers an article [beyond that distance], he is not liable, because he is located in a different domain.2The Ra'avad questions the Rambam's decision, noting that Eruvin 99a would appear to hold a person liable in such a situation. The difficulty with the Rambam's statements is compounded by the fact that the passage cited above associates the law in question with the following decision, "A person who carries an article from the beginning [of a square] four cubits long to the end [of that square] in the public domain is liable, even when he lifts it above his head." Since the Rambam holds one liable in the latter instance (see Chapter 12, Halachah 14), it would seem that he would hold one liable with regard to the law under discussion. The Ra'avad's arguments are so powerful that the Maggid Mishneh suggests amending the text of the Mishneh Torah accordingly.
The Radbaz (Vol. V, Responsum 1527) notes the Ra'avad's question, and states that he checked all the ancient manuscripts of the Mishneh Torah available to him, and they all state that the person is not liable. Therefore, he explains that a person is not liable for transfering an article unless he is standing in one of the domains involved in the transfer. This concept is derived from the transfer of the articles in the construction of the Sanctuary. In this instance, the people were not standing in a domain other than those involved in the transfer. Based on this foundation, he offers an interpretation - albeit a slightly strained one - for the passage in Eruvin.

Similarly, a person standing in a private domain may open [a door with a key3This and the following law refer to situations where the key is located in the domain where the door is located.] in a public domain.4The Maggid Mishneh mentions the possibility of placing the key in the door as a forbidden transfer. In the present day, almost every keyhole would be considered to be a makom patur. [One standing] in a public domain may open [a door with a key] in a private domain.
One may force feed an animal whose head is inside [a stall, although] the major portion of its body is outside.5I.e., we are not worried that perhaps the animal will withdraw its neck and the person will carry the food outside the stall. Note the apparent contradiction to Chapter 17, Halachah 29. One may not, [however, force feed a] camel unless its head and the major portion of its body is within [the stall], since its neck is long.

הלכה ב
לֹא יַעֲמֹד אָדָם בִּרְשׁוּת הַיָּחִיד וְיִשְׁתֶּה בִּרְשׁוּת הָרַבִּים. בִּרְשׁוּת הָרַבִּים וְיִשְׁתֶּה בִּרְשׁוּת הַיָּחִיד. אֶלָּא אִם כֵּן הִכְנִיס רֹאשׁוֹ וְרֻבּוֹ לְמָקוֹם שֶׁהוּא שׁוֹתֶה. בַּמֶּה דְּבָרִים אֲמוּרִים כְּשֶׁהָיָה שׁוֹתֶה בְּכֵלִים נָאִים שֶׁהוּא צָרִיךְ לָהֶן. גְּזֵרָה שֶׁמָּא יוֹצִיאֵם. אֲבָל אִם הָיוּ כֵּלִים שֶׁאֵינָן נָאִים שֶׁאֵינוֹ צָרִיךְ לָהֶן. אוֹ שֶׁהָיָה הַבּוֹר בְּכַרְמְלִית אַף עַל פִּי שֶׁהַכֵּלִים נָאִים. מַכְנִיס רֹאשׁוֹ בִּלְבַד וְשׁוֹתֶה בִּמְקוֹמוֹ וְאַף עַל פִּי שֶׁלֹּא הִכְנִיס רֹאשׁוֹ וְרֻבּוֹ:
כסף משנה
2.
A person should not stand in a private domain and [extend his head into] the public domain to drink, nor [should he stand] in a public domain and [extend his head into] a private domain to drink, unless he brings his head and the majority of his body into the domain in which he is drinking.
When do the above [restrictions] apply? When he is drinking with attractive vessels that he needs.6As mentioned in the notes on the previous halachah, in their commentary on Eruvin 99a, the source for these halachot, Rashi and the Rashba maintain that if the person requires the vessels, the above restrictions apply even if the vessels are not attractive. The Maggid Mishneh states that although the Rambam's ruling appears most appropriate within the context of the Talmudic passage, in practice the more stringent ruling should be followed. As mentioned, the Shulchan Aruch also rules accordingly. [In this instance, our Sages instituted a] decree, lest he transfer [the drinking vessels]. If, however, [the person uses] vessels that are not attractive and which he does not require, all that is necessary is that he bring in his head; it is not necessary that he bring in the majority of his body.7This relects a significant leniency. We are requiring the person to drink while bent over. Even so, the Rabbis did not feel it necessary to forbid the person from drinking, lest he forget, stand upright, and thus bring the drinking vessel into the other domain. If a cistern of water is located in a carmelit, [the above leniency applies] even when [the person] uses vessels that are attractive.8The prohibition against transferring an article from a carmelit is Rabbinic in nature. Hence, even if the person were to forget and transfer the drinking vessels to his domain, he would not violate Torah law. Accordingly, there is no need to prohibit him from drinking as a further safeguard.
This represents the opinion of Ravvah (Eruvin 99a) and is accepted by the Shulchan Aruch (Orach Chayim 350:1). Significantly, however, the Talmud also records the opinion of Abbaye, who differs and maintains that since the forbidden labor of transferring articles is a matter that may be taken lightly, the Sages instituted safeguards with regard to Rabbinic decrees as well.

הלכה ג
עוֹמֵד אָדָם בִּרְשׁוּת הָרַבִּים וְקוֹלֵט מִן הָאֲוִיר מִן הַמַּיִם הַמְקַלְּחִין מִן הַצִּנּוֹר אוֹ מִן הַכֹּתֶל וְשׁוֹתֶה. וּבִלְבַד שֶׁלֹּא יִגַּע בַּצִּנּוֹר אוֹ בַּכֹּתֶל וְיִקְלֹט מֵעַל גַּבָּן. וְאִם נָגַע אִם הָיָה מָקוֹם שֶׁנָּגַע בּוֹ לְמַעְלָה מֵעֲשָׂרָה בְּפָחוֹת מִשְּׁלֹשָׁה סָמוּךְ לַגַּג הֲרֵי זֶה אָסוּר. שֶׁנִּמְצָא כְּעוֹקֵר מֵעַל הַגַּג שֶׁהוּא רְשׁוּת הַיָּחִיד. וְכֵן אִם הָיָה בַּצִּנּוֹר אַרְבָּעָה עַל אַרְבָּעָה בֵּין שֶׁהָיָה הַצִּנּוֹר בְּתוֹךְ עֲשָׂרָה בֵּין שֶׁהָיָה לְמַעְלָה מֵעֲשָׂרָה וְקָלַט מִמֶּנּוּ מַיִם הֲרֵי זֶה אָסוּר. וְלָמָּה אֵינוֹ חַיָּב מִפְּנֵי שֶׁלֹּא נָחוּ הַמַּיִם אֶלָּא הֲרֵי הֵן נִזְחָלִין וְהוֹלְכִין:
כסף משנה
3.
A person may stand in a public domain, [extend his hand,] collect water that is flowing from a drainpipe or a wall [while the water is] in the air, and drink, provided he does not touch the drainpipe or the wall and collect the water from them.9As long as he takes the water from the air, there is no difficulty. If he takes the water from ten handbreadths or more above the ground, he has taken it from a makom patur. If he takes it from less than ten handbreadths, he has moved an article less than four cubits in the public domain.
[The following rules apply] should he [in fact] touch [the drainpipe or the wall]: If the place he touches is more than ten [handbreadths] high and within three handbreadths of the roof, the act is forbidden.10Based on the principle of l'vud, since the pipe is within three handbreadths of a private domain, it is considered to be an extension of that domain.
From the Rambam's wording, it appears that if the roof is less than thirteen handbreadths above the ground, the principle of l'vud does not apply. This is so because the principle of l'vud cannot cause a space that is part of the public domain to be considered an extension of a private domain (Maggid Mishneh).
It is as if he removed [the water] from the roof, which is a private domain.
Similarly, if the drainpipe was four [handbreadths] by four [handbreadths] and one collected water from it, this is forbidden regardless of whether the pipe is within ten handbreadths of the ground11In this instance, the pipe would be considered to be a carmelit. Transferring from a carmelit to a public domain is forbidden. or above ten handbreadths.12In this instance, the drainpipe is considered to be a private domain in its own right. Why is the person not held liable? Because the water is not at rest, but rather continuing to flow.13Note the distinction between this ruling and Chapter 13, Halachah 4, which describes removing water that is at rest.

הלכה ד
זִיז שֶׁלִּפְנֵי הַחַלּוֹן יוֹצֵא בָּאֲוִיר שֶׁעַל רְשׁוּת הָרַבִּים. אִם הָיָה לְמַעְלָה מֵעֲשָׂרָה טְפָחִים מֻתָּר לְהִשְׁתַּמֵּשׁ עָלָיו שֶׁאֵין רְשׁוּת הָרַבִּים תוֹפֶסֶת אֶלָּא עֲשָׂרָה טְפָחִים. לְפִיכָךְ מֻתָּר לְהִשְׁתַּמֵּשׁ בְּכָל הַכֹּתֶל עַד עֲשָׂרָה טְפָחִים הַתַּחְתּוֹנִים:
כסף משנה
4.
[The following rules apply when] a projection extends [from the wall of a building] near a window: If the projection is above ten handbreadths high, its use is permitted,14I.e., to place articles upon it, transferring them from the building. Note, however, the restrictions mentioned in Halachah 7. for the public domain extends only ten handbreadths [above the ground].15The space more than ten handbreadths above a public domain is a makom patur. Hence, one may transfer articles to and from it (Chapter 14, Halachah 12). Therefore, it is permissible to use the entire wall, with the exception of the bottom ten handbreadths.16This applies even if a projection is four handbreadths by four handbreadths in area and directly below an open window. Since it is low enough to be used by the passersby in the public domain, it is considered to be a carmelit.

הלכה ה
בַּמֶּה דְּבָרִים אֲמוּרִים כְּשֶׁהָיָה זִיז אֶחָד יוֹצֵא בָּאֲוִיר. אֲבָל אִם הָיוּ יוֹצְאִים בַּכֹּתֶל שְׁנֵי זִיזִין זֶה לְמַטָּה מִזֶּה אַף עַל פִּי שֶׁשְּׁנֵיהֶם לְמַעְלָה מֵעֲשָׂרָה. אִם יֵשׁ בַּזִּיז הָעֶלְיוֹן שֶׁלִּפְנֵי הַחַלּוֹן רֹחַב אַרְבָּעָה עַל אַרְבָּעָה אָסוּר לְהִשְׁתַּמֵּשׁ עָלָיו. מִפְּנֵי שֶׁהוּא רְשׁוּת בִּפְנֵי עַצְמוֹ וְהַזִּיז שֶׁתַּחְתָּיו רְשׁוּת אַחֶרֶת. וְאָסְרוּ זֶה עַל זֶה. שֶׁאֵין שְׁתֵּי רְשׁוּיוֹת מִשְׁתַּמְּשׁוֹת בִּרְשׁוּת אַחַת:
כסף משנה
5.
When does the above apply? When there is [only] one projection extending into the space. When, however, there are two projections extending from the wall, one below the other,17The Maggid Mishneh explains that according to the Rambam, these restrictions apply even when the two projections are not directly above each other. even though they are both more than ten handbreadths high,18As the Rambam explains, the difficulty is that people from different properties cannot both use a third property which adjoins them - for example (Hilchot Eruvin 3:16), a wall that is four handbreadths wide that separates between two different properties. In particular, there are two conceptions of the Rambam's statements:
a) that of the Shulchan Aruch (Orach Chayim 353:2), which explains that the two projections extend from two windows belonging to two different individuals who have not made an eruv. Since these individuals are forbidden to transfer articles from one projection to the other by Rabbinical decree, certain restrictions were also placed on using the projections themselves.
b) that of the Ritba, who explains that we are speaking of a wall that possesses only a single window. Nevertheless, the lower projection may be used by the passersby in the public domain. (Although the public domain extends only to ten handbreadths, the people in the public domain have the right to use projections and holes in the wall that are above that height.) When there is only one projection, they refrain from using it, because it will be used by the inhabitants of the house. When, however, there are two projections, the passersby feel free to use the lower one. This in turn causes there to be certain restrictions with regard to the use of both projections on the Sabbath. See the diagram on the opposite page.
Although the Merkevet HaMishneh and others explain that the Ritba's interpretation is more appropriate to the wording chosen by the Rambam, our notes will follow the approach of the Shulchan Aruch, for it is accepted by the subsequent halachic authorities. It also must be noted that Rashi's version of the text of Eruvin 98b differs from that of the Rambam. Accordingly, he and the subsequent Ashkenazic authorities have a different conception of these rulings.
[different rules apply]: If the upper projection near the window is four [handbreadths] by four [handbreadths] in area, its use is forbidden,19Note that Shulchan Aruch HaRav 353:3 and the Mishnah Berurah 353:11 explain that this refers to articles that were kept inside the house. Articles that were left on the projection before the Sabbath may be moved on it. See Hilchot Eruvin 3:18-19. for it is a domain in its own right, and the projection below it is a separate domain.20This applies even if the lower projection is not four handbreadths by four handbreadths (Shulchan Aruch HaRav 353:4; Mishnah Berurah 353:12). Accordingly, they each cause the other to be forbidden,21Note the Mishnah Berurah 353:12, which cites opinions that allow the people whose window opens up to the lower projection to use it when it is less than four handbreadths by four handbreadths. for [the people in] two domains cannot [jointly] use the space of one domain.

הלכה ו
אֵין בָּעֶלְיוֹן אַרְבָּעָה וְאֵין בַּתַּחְתּוֹן אַרְבָּעָה. מִשְׁתַּמֵּשׁ בִּשְׁנֵיהֶן וְכֵן בְּכָל הַכֹּתֶל עַד עֲשָׂרָה טְפָחִים הַתַּחְתּוֹנִים. הָיָה בַּתַּחְתּוֹן אַרְבָּעָה וְהָעֶלְיוֹן אֵין בּוֹ אַרְבָּעָה אֵינוֹ מִשְׁתַּמֵּשׁ בָּעֶלְיוֹן אֶלָּא כְּנֶגֶד חַלּוֹנוֹ בִּלְבַד. אֲבָל בִּשְׁאָר הַזִּיז שֶׁבִּשְׁנֵי צִדְדֵי הַחַלּוֹן אָסוּר לְהִשְׁתַּמֵּשׁ מִפְּנֵי זֶה שֶׁתַּחְתָּיו שֶׁחָלַק רְשׁוּת לְעַצְמוֹ:
כסף משנה
6.
If both the upper projection and the lower projection are not four [handbreadths by four handbreadths], both of them may be used.22There are no restrictions whatsoever, for neither projection is a domain in its own right. Similarly, [in such a situation,] one may use the entire wall with the exception of the bottom ten handbreadths.
If the lower projection was four [handbreadths by four handbreadths], but the upper projection was not four [handbreadths by four handbreadths], [an individual dwelling in the upper storey] may use only that portion of the upper [projection] that is directly opposite his window.23This is permitted, because the projection is considered to be an extension of the window, like a hole in the wall of a private domain (Maggid Mishneh). It is forbidden to use the remainder of the projection that extends on either side of the window, because of the lower projection, which is considered to be a separate domain.24Since the lower projection is a domain in its own right, it includes the space above it until the heavens, and the entire wall is considered as a part of it. In this instance, since the upper projection is not considered to be a domain in its own right, it is divided into portions. The portion directly opposite the window is considered an extension of the window as in the previous note, but the portion on either side is considered part of the lower projection.

הלכה ז
כָּל זִיז הַיּוֹצֵא עַל אֲוִיר רְשׁוּת הָרַבִּים שֶׁמֻּתָּר לְהִשְׁתַּמֵּשׁ עָלָיו. כְּשֶׁהוּא מִשְׁתַּמֵּשׁ בּוֹ אֵין נוֹתְנִין עָלָיו וְאֵין נוֹטְלִין מִמֶּנּוּ אֶלָּא כְּלֵי חֶרֶס וּזְכוּכִית וְכַיּוֹצֵא בָּהֶן שֶׁאִם יִפְּלוּ לִרְשׁוּת הָרַבִּים יִשָּׁבְרוּ. אֲבָל שְׁאָר כֵּלִים וָאֳכָלִין אֲסוּרִים שֶׁמָּא יִפְּלוּ לִרְשׁוּת הָרַבִּים וִיבִיאֵם:
כסף משנה
7.
Whenever there is a projection that extends over the public domain25If the projection extends over a carmelit and is ten handbreadths high, there are no restrictions regarding the articles that may be used on it (Shulchan Aruch, Orach Chayim 353:3). and may be used, one may place upon it and remove from it only utensils of earthenware, glass, or the like, for if they fall into the public domain they will break. Other utensils and food are prohibited [to be placed there], lest they fall into the public domain, and [one descend and] bring them [into the home].26Bringing the articles from the public domain to the home constitutes a forbidden activity. Hence, our Sages instituted this safeguard.
Note the Rashba, who states that if a projection is four handbreadths by four handbreadths, there are no restrictions regarding the articles that may be used on it. Although the Shulchan Aruch (Orach Chayim 353:3) quotes the Rambam's ruling, the Ramah states that on a roof or balcony on which a person stands comfortably, all articles may be carried.

הלכה ח
שְׁנֵי בָּתִּים בִּשְׁנֵי צִדֵּי רְשׁוּת הָרַבִּים זָרַק מִזּוֹ לָזוֹ לְמַעְלָה מֵעֲשָׂרָה פָּטוּר וְהוּא שֶׁיִּהְיוּ שְׁנֵיהֶם שֶׁלּוֹ אוֹ שֶׁיִּהְיֶה בֵּינֵיהֶם עֵרוּב. וַאֲפִלּוּ בְּגָדִים וּכְלֵי מַתָּכוֹת מֻתָּר לִזְרֹק. וְאִם הָיָה זֶה לְמַעְלָה מִזֶּה וְלֹא הָיָה בְּשָׁוֶה אָסוּר לִזְרֹק בֶּגֶד וְכַיּוֹצֵא בּוֹ שֶׁמָּא יִפּל וִיבִיאֶנּוּ. אֲבָל כְּלֵי חֶרֶס וְכַיּוֹצֵא בָּהֶן זוֹרֵק:
כסף משנה
8.
[The following rules apply when] there are two houses on opposite sides of the public domain: If a person throws an article from one to the other and the article is ten [handbreadths] above the ground, he is not liable,27Our translation follows the version of the standard published text of the Mishneh Torah. Many early printings and manuscripts of the text state "one is permitted...." From the context, the latter version appears more appropriate.
One is forbidden to transfer from one private domain to another private domain when they are separated by a public domain. Nevertheless, since the public domain extends for only ten handbreadths above the ground, the transfer is not being made through a public domain, but rather through a makom patur (Shulchan Aruch HaRav 353:1).
provided both houses belong to him or there is an eruv between them.28See Hilchot Eruvin 1:1-4, which explains that although according to the Torah itself, one may transfer from one private domain to another, our Sages forbade this unless an eruv was constructed. One may throw even garments and metal utensils.29These articles are not breakable. Nevertheless, since the houses are on the same level, it is not difficult to throw from one to the other. Accordingly, our Sages did not feel the need for a safeguard, lest the article fall and the person descend to the public domain and bring them into his home, a private domain.
Two Houses of Different Heights on Opposite Sides of the Public Domain
If one of [the two houses] was higher than the other, and they were thus not on the same level, it is forbidden to throw a garment or the like, lest it fall and [one descend and] bring it. One may, however, throw earthenware utensils and the like.30Even if the articles fall into the public domain, they will break. Hence, there is no need to worry that the person may bring them home.
The above restrictions apply only to houses on two sides of a public domain. If two houses are located on two sides of a carmelit, there are no restrictions regarding the type of articles that may be thrown, because there is no possibility of a Torah prohibition being violated (Maggid Mishneh).

הלכה ט
בּוֹר בִּרְשׁוּת הָרַבִּים וְחַלּוֹן עַל גַּבָּיו הַבּוֹר וְחֻלְיָתוֹ מִצְטָרְפִים לַעֲשָׂרָה וּמְמַלְּאִין מִמֶּנּוּ בְּשַׁבָּת. בַּמֶּה דְּבָרִים אֲמוּרִים כְּשֶׁהָיָה סָמוּךְ לַכֹּתֶל בְּתוֹךְ אַרְבָּעָה טְפָחִים שֶׁאֵין אָדָם יָכוֹל לַעֲבֹר שָׁם. אֲבָל אִם הָיָה מֻפְלָג אֵין מְמַלְּאִין מִמֶּנּוּ אֶלָּא אִם כֵּן הָיְתָה חֻלְיָתוֹ גְּבוֹהָה עֲשָׂרָה שֶׁנִּמְצָא הַדְּלִי כְּשֶׁיֵּצֵא מִן הַחֻלְיָא יֵצֵא לִמְקוֹם פְּטוֹר:
כסף משנה
9.
[The following rules apply when] a cistern located in the public domain has an opening [to a home] above it: The cistern and the sand [piled around it] are measured together [to see if their height reaches] ten [handbreadths]. [If it does,31A cistern that is ten handbreadths deep is considered as a private domain. Were the sand piled around the cistern to be ten handbreadths high, the enclosure would be considered a private domain. Eruvin 99b teaches us a new concept, that the sum of ten handbreadths can be reached by combining the two together.
Hence, there is no difficulty in drawing water from the enclosure to the house, since one is transferring from one private domain to another. Needless to say, it is forbidden to transfer from such an enclosure to the public domain.
] one may draw water from it on the Sabbath.
When does the above apply? When [the cistern] is within four handbreadths of the wall, for then a person cannot pass between them.32Since there is no room for a person to pass comfortably between the sand pile and the wall of the house, the space between them is not considered as part of the public domain, but rather as a carmelit (compare to Chapter 14, Halachah 6). Therefore, the space above it is also considered as a carmelit. Thus, one would be transferring from a private domain to a private domain via a carmelit. In this instance (in contrast to Chapter 14, Halachah 14), our Sages allowed such a transfer. If, however, it is further removed,33When there is room for people to pass between the cistern and the house in a normal manner, the space between them is considered as part of the public domain. Therefore, a person who draws water through the opening to his home would be considered to be transferring from a private domain - the cistern - through a public domain - the area above the space between the sand pile and the home - to one's home - a private domain. See Chapter 13, Halachah 16. one may not draw water from it unless the sand [piled around it] is ten [handbreadths] high.34Here, the importance of the height of ten handbreadths is not significant because it creates a private domain, but because, as explained in the following note, this will cause the bucket to be more than ten handbreadths above the ground as it passes over the sand pile. Thus, when the bucket is raised above the sand [pile],35I.e., as the bucket is transferred from the enclosure to the home, it passes above the public domain. In this instance, since the sand pile is ten handbreadths high, there is no difficulty, because the space ten handbreadths above the public domain is a makom patur. it enters a makom patur.

הלכה י
אַשְׁפָּה בִּרְשׁוּת הָרַבִּים גְּבוֹהָה עֲשָׂרָה טְפָחִים וְחַלּוֹן עַל גַּבָּהּ שׁוֹפְכִין לָהּ מַיִם בְּשַׁבָּת. בַּמֶּה דְּבָרִים אֲמוּרִים בְּאַשְׁפָּה שֶׁל רַבִּים שֶׁאֵין דַּרְכָּהּ לְהִפָּנוֹת. אֲבָל שֶׁל יָחִיד אֵין שׁוֹפְכִין עָלֶיהָ שֶׁמָּא תִּתְפַּנֶּה וְנִמְצְאוּ שׁוֹפְכִין כְּדַרְכָּן בִּרְשׁוּת הָרַבִּים:
כסף משנה
10.
It is permitted to pour water [from] a window [of a home] to a garbage heap located in the public domain that is ten handbreadths high, on the Sabbath.36Since the garbage heap is ten handbreadths high, it constitutes a private domain.
Thus, when water is poured from the house, the water will pass from a private domain through a makom patur - the space more than ten handbreadths above the public domain - to another private domain. This is permitted.

To what does the above apply? To a garbage heap belonging to the community, for this is unlikely to be removed. We may not, however, pour water onto a garbage heap belonging to an individual.37This is a Rabbinic decree, instituted for the reason to be explained. Shulchan Aruch HaRav 354:3 states that this restriction applies even if the garbage heap is located in a carmelit.
It is possible that the garbage heap was cleared away 38Eruvin 99b cites an example where the Sages considered such a possibility. and thus, [unknowingly,39I.e., we suspect that without looking, the person will follow his usual habit and pour water onto the place where the garbage heap was located previously without noticing that it had been removed.] one will be pouring into the public domain.

הלכה יא
אַמַּת הַמַּיִם שֶׁהִיא עוֹבֶרֶת בֶּחָצֵר אִם יֵשׁ בְּגָבְהָהּ עֲשָׂרָה טְפָחִים וּבְרָחְבָּהּ אַרְבָּעָה אוֹ יוֹתֵר עַל כֵּן עַד עֶשֶׂר אַמּוֹת אֵין מְמַלְּאִין מִמֶּנָּה בְּשַׁבָּת אֶלָּא אִם כֵּן עָשׂוּ לָהּ מְחִצָּה גְּבוֹהָה עֲשָׂרָה טְפָחִים בַּכְּנִיסָה וּבַיְצִיאָה. וְאִם אֵין בְּגָבְהָהּ עֲשָׂרָה אוֹ שֶׁאֵין בְּרָחְבָּהּ אַרְבָּעָה מְמַלְּאִין מִמֶּנָּה בְּלֹא מְחִצָּה:
כסף משנה
11.
[The following rules apply to] a water conduit that passes through a courtyard: If it is ten [handbreadths] high and between four [handbreadths] and ten cubits wide, we may not draw water from it on the Sabbath, unless one erects a partition [in the water] ten handbreadths high at its entrance [to the courtyard] and its exit.
If it is not ten [handbreadths] high or is less than four [handbreadths] wide, we may draw water from it without [erecting] a partition.

הלכה יב
הָיָה בְּרָחְבָּהּ יֶתֶר מֵעֶשֶׂר אַמּוֹת אַף עַל פִּי שֶׁאֵין בְּגָבְהָהּ עֲשָׂרָה אֵין מְמַלְּאִין מִמֶּנָּה עַד שֶׁיַּעֲשֶׂה לָהּ מְחִצָּה. שֶׁכָּל יֶתֶר עַל עֶשֶׂר פִּרְצָה הִיא וּמַפְסֶדֶת הַמְּחִצּוֹת. וּמַהוּ לְטַלְטֵל בְּכָל הֶחָצֵר. אִם נִשְׁאַר מִצַּד הַפִּרְצָה פַּס מִכָּאן וּפַס מִכָּאן בְּכָל שֶׁהוּא אוֹ פַּס רֹחַב אַרְבָּעָה טְפָחִים מֵרוּחַ אַחַת מֻתָּר לְטַלְטֵל בְּכָל הֶחָצֵר וְאֵין אָסוּר אֶלָּא לְמַלְּאוֹת מִן הָאַמָּה בִּלְבַד. אֲבָל אִם לֹא נִשְׁאַר פַּס כְּלָל אָסוּר לְטַלְטֵל בְּכָל הֶחָצֵר שֶׁהֲרֵי נִפְרְצָה חָצֵר לַיָּם שֶׁהוּא כַּרְמְלִית:
כסף משנה
12.
When [the water conduit that passes through the courtyard]40In this halachah as well, most commentaries maintain that the Rambam is referring to a water conduit that passes through a place where a portion of the wall of the courtyard has been taken down. As mentioned above, the Ra'avad interprets Eruvin 12b, the source for this halachah, differently, and therefore objects to the Rambam's ruling.

Significantly, the Merkevet HaMishneh notes that the second clause of the halachah appears to indicate that the conduit breaks through the wall entirely, and it therefore offers a different interpretation of the Rambam's words.
is more than ten cubits wide, although it is less than ten handbreadths high, we may not draw water from it unless a partition is erected. Since it is more than ten [cubits] wide, it is considered to be an open space and nullifies the existence of the divider.41Since the conduit is not deep enough to constitute a domain of its own, it would normally be considered part of the domain through which it passes. (See Chapter 14, Halachah 24.) Nevertheless, since this conduit is so wide, it is no longer considered part of the private domain.
What is the ruling regarding carrying in the courtyard as a whole?42I.e., does the conduit nullify the courtyard's distinction as a private domain? Significantly, this question is asked in this halachah and not in the previous one. In the previous halachah, although the conduit itself was considered a separate domain, since the opening was less than ten handbreadths, it is considered as an entrance and the enclosure is not nullified. This halachah, however, mentions an opening of more than ten cubits, an aperture which ordinarily nullifies an enclosure. If there is even a small portion [of the wall] remaining on both sides of the opening, or if a portion [of the wall] four handbreadths in size remains on one side of the opening, it is permitted to carry in the entire courtyard.43Several explanations have been offered for the Rambam's ruling. Among them: the small portion of the wall which remains juts out over the water. Therefore, the opening to the courtyard is less than ten cubits (Rabbenu Yonason, commenting on Rabbenu Yitzchak Alfasi). The portions of the wall which remain on either side are considered like poles. As stated in Chapter 17, Halachah 7, it is permitted to carry in a courtyard with poles on either edges of the entrance to the fourth side (an ancient commentary on the Mishneh Torah from Egypt). See also the Or Sameach. It is forbidden only to draw water from the conduit.44For the reasons mentioned above, the wall of the courtyard is an acceptable divider, and thus the courtyard as a whole is still considered to be a private domain. Nevertheless, since the wall was not made for the purpose of distinguishing the water that is outside the courtyard from that which is within the courtyard, a separate partition is required for that purpose (ibid.). If, however, no portion of the wall remains, it is forbidden to carry in the entire courtyard, for it has been opened up to the sea,45When there are no portions jutting out over the water (according to the first interpretation in note 49) or when the entire wall is destroyed (according to the second), the courtyard is considered as enclosed on three sides alone and it is forbidden to carry within. which is a carmelit.

הלכה יג
וְהֵיאַךְ מַעֲמִידִין אֶת הַמְּחִצָּה בְּמַיִם. אִם הָיְתָה לְמַעְלָה מִן הַמַּיִם צָרִיךְ שֶׁיִּהְיֶה טֶפַח מִן הַמְּחִצָּה יוֹרֵד בְּתוֹךְ הַמַּיִם. וְאִם הָיְתָה הַמְּחִצָּה כֻּלָּהּ יוֹרֶדֶת בְּתוֹךְ הַמַּיִם צָרִיךְ שֶׁיִּהְיֶה טֶפַח מִמֶּנָּה יוֹצֵא לְמַעְלָה מִן הַמַּיִם. כְּדֵי שֶׁיִּהְיוּ הַמַּיִם שֶׁבֶּחָצֵר מֻבְדָּלִין אַף עַל פִּי שֶׁאֵין הַמְּחִצָּה מַגַּעַת עַד הַקַּרְקַע הוֹאִיל וְיֵשׁ בָּהּ עֲשָׂרָה טְפָחִים הֲרֵי זוֹ מֻתֶּרֶת. וְלֹא הִתִּירוּ מְחִצָּה תְּלוּיָה אֶלָּא בְּמַיִם בִּלְבַד. שֶׁאִסּוּר טִלְטוּל בְּמַיִם מִדִּבְרֵיהֶם וְהֵקֵלוּ בִּמְחִצָּה שֶׁאֵינָהּ אֶלָּא כְּדֵי לַעֲשׂוֹת הֶכֵּר:
כסף משנה
13.
How must the partitions be erected in the water? If [the majority of the partition] is above the water, at least a handbreadth of the partition must descend into the water.46For the entire intent of this partition is to make a distinct separation between the water in the courtyard and the water in the public domain outside of it. [See the Rambam's Commentary on the Mishneh (Eruvin 8:6). See also Hilchot Eruvin 3:21-22 where the Rambam mentions a similar requirement.] If the partition as a whole descends into the water, at least a handbreadth must rise above the water level. [In this manner,] the water in the courtyard will be distinct, [from the water in the conduit on either side of the courtyard].
Although the partition does not reach the ground [in the conduit], since it is ten handbreadths high, it is permitted. The use of a partition that remains hanging was allowed only with regard to water.47Generally, a partition must descend within three handbreadths of the ground. Since the prohibition against carrying this water is Rabbinic in origin,48For, as mentioned above, the courtyard is a private domain, and carrying within it is permitted. Furthermore, even the water conduit is considered as a private domain according to the Torah itself and its designation as a carmelit is Rabbinic in origin. [the Sages] were lenient regarding [the nature of] the partition [required], for its purpose is only to create a distinction.

הלכה יד
אַמַּת הַמַּיִם הָעוֹבֶרֶת בֵּין הַחֲצֵרוֹת וְחַלּוֹנוֹת פְּתוּחוֹת אֵלֶיהָ. אִם אֵין בָּהּ כַּשִּׁעוּר מְשַׁלְשְׁלִין דְּלִי מִן הַחַלּוֹנוֹת וּמְמַלְּאִים מִמֶּנָּה בְּשַׁבָּת. בַּמֶּה דְּבָרִים אֲמוּרִים בְּשֶׁאֵינָהּ מֻפְלֶגֶת מִן הַכֹּתֶל שְׁלֹשָׁה טְפָחִים. אֲבָל אִם הָיְתָה מֻפְלֶגֶת מִן הַכֹּתֶל שְׁלֹשָׁה טְפָחִים אֵין מְמַלְּאִים מִמֶּנָּה אֶלָּא אִם כֵּן הָיוּ פַּסִּין יוֹצְאִין מִן הַכְּתָלִים מִכָּאן וּמִכָּאן שֶׁנִּמְצָא הָאַמָּה כְּאִלּוּ הִיא עוֹבֶרֶת בְּתוֹךְ הֶחָצֵר:
כסף משנה
14.
[The following rules apply] when a conduit of water passes between several courtyards and there are openings [from the courtyards] to it:49In contrast to the conduit mentioned in the previous halachot, this conduit does not pass through the courtyards, but merely by their side. Hence, it cannot be considered as part of the courtyard itself. If it is not the minimum size [of a domain],50I.e., ten handbreadths deep and four handbreadths wide.one may lower buckets from the windows and draw water from it on the Sabbath.51The conduit is considered to be a carmelit; the windows, the holes adjacent to a carmelit. One may transfer an article from a carmelit to such holes. This interpretation follows Rabbenu Chanan'el's interpretation of Eruvin 87b. The Ra'avad has a different conception of this passage, and hence objects to the Rambam's rulings.
The extension of the wall 3 handbreadths
When does the above apply? When [the conduit] is not more than three handbreadths away from the wall. If, however, [the conduit] is more than three handbreadths away from the wall, we may not draw water from it52Since the opening is more than three handbreadths away, it is no longer considered to be a hole adjacent to the carmelit, but rather a separate entity. Hence, it is forbidden to transfer from the carmelit to it. unless there are projections extending from the walls on either side. Thus the conduit would be considered as if it passes through the courtyard.53I.e., the projections would cause the courtyard to be considered as extending beyond its wall, into the space of the conduit. Therefore, taking water from the conduit would be considered as moving an article within a single private domain.

הלכה טו
כְּצוֹצְרָה שֶׁהִיא לְמַעְלָה מִן הַיָּם וְחַלּוֹן בְּתוֹכָהּ עַל גַּבֵּי הַמַּיִם. אֵין מְמַלְּאִים מִמֶּנָּה בְּשַׁבָּת אֶלָּא אִם כֵּן עָשׂוּ מְחִצָּה גְּבוֹהָה עֲשָׂרָה טְפָחִים עַל גַּבֵּי הַמַּיִם כְּנֶגֶד הַחַלּוֹן שֶׁבַּכְּצוֹצְרָה. אוֹ תִּהְיֶה הַמְּחִצָּה יוֹרֶדֶת מִן הַכְּצוֹצְרָה כְּנֶגֶד הַמַּיִם וְרוֹאִין אוֹתָהּ כְּאִלּוּ יָרְדָה וְנָגְעָה עַד הַמַּיִם. וּכְשֵׁם שֶׁמְּמַלְּאִין מִזּוֹ שֶׁעָשׂוּ לָהּ מְחִצָּה כָּךְ שׁוֹפְכִין מִמֶּנָּה עַל הַיָּם. שֶׁהֲרֵי עַל הַכַּרְמְלִית הֵן שׁוֹפְכִין:
כסף משנה
15.
[The following rules govern] a balcony54In his Commentary on the Mishnah (Eruvin 8:8), the Rambam explains that just as it is customary to erect balconies over the public domain, it is also customary to erect balconies over bodies of water. that extends over a body of water with an aperture55The Shulchan Aruch (Orach Chayim 355:1) states that the aperture must be four handbreadths by four handbreadths. [in its floor] that opens to the water: We may not draw water from it on the Sabbath56Since the body of water is considered to be a carmelit. It is forbidden to transfer from a carmelit to a private domain. unless a partition ten handbreadths high is constructed over the water parallel to the opening in the balcony.57The partition need not reach the water itself. Because of the principle gud acheit mechitzata, the partition is considered as if it extends into the water, even though it actually ends above its surface. This leniency is granted, because the entire prohibition is Rabbinic in origin.




Thus it is considered as if the hole extends into the water itself. Accordingly, we are allowed to draw water through it, because the portion of the body of water beneath it is considered to be an extension of the private domain [the Rambam's Commentary on the Mishnah (ibid.)].
Alternatively, we may construct a partition descending from the balcony to the water. Then, we consider this partition as descending until it touches the water.58The partition need not reach the balcony. Because of the principle gud asik mechitzata, the partition is considered as if it extends to the balcony, even though it actually ends below it (ibid.). See also Shulchan Aruch (Orach Chayim 355:1).
Just as we may draw water from [the body of water] after making the partition, so too we may pour water from the balcony to the water.59Eruvin 88a explains that the leniency of pouring into the body of water has an added dimension of severity. The current of the water will cause the water that has been poured to flow beyond the periphery of the aperture and into the portion of the body of water that is a carmelit. Nevertheless, since the person does not perform this transfer himself, there is no restriction. [The rationale is:] One is pouring into a carmelit.60Since the prohibition is Rabbinic in origin, the construction of such a partition is sufficient (Ma'aseh Rokeach).

הלכה טז
חָצֵר שֶׁהִיא פְּחוּתָה מֵאַרְבַּע אַמּוֹת עַל אַרְבַּע אַמּוֹת אֵין שׁוֹפְכִין בְּתוֹכָהּ מַיִם בְּשַׁבָּת מִפְּנֵי שֶׁהֵן יוֹצְאִין לִרְשׁוּת הָרַבִּים בִּמְהֵרָה. לְפִיכָךְ צָרִיךְ לַעֲשׂוֹת גּוּמָה מַחְזֶקֶת סָאתַיִם בְּתוֹךְ הֶחָצֵר אוֹ בִּרְשׁוּת הָרַבִּים בְּצַד הֶחָצֵר כְּדֵי שֶׁיִּהְיוּ הַמַּיִם נִקְבָּצִים בְּתוֹכָהּ. וְצָרִיךְ לִבְנוֹת עָלֶיהָ כִּפָּה מִבַּחוּץ כְּדֵי שֶׁלֹּא תֵּרָאֶה הָעוּקָה הַזֹּאת בִּרְשׁוּת הָרַבִּים. וְהֶחָצֵר וְהָאַכְסַדְרָה מִצְטָרְפִין לְאַרְבַּע אַמּוֹת. וְכַמָּה הוּא הַמָּקוֹם שֶׁמַּחֲזִיק סָאתַיִם חֲצִי אַמָּה עַל חֲצִי אַמָּה בְּרוּם שְׁלֹשָׁה חֻמְשֵׁי אַמָּה:
כסף משנה
16.
We must not pour water into a courtyard that is less than four cubits by four cubits61The Maggid Mishneh explains that the Rambam's wording is intended to negate an opinion mentioned in Eruvin 88a, which states that even if a courtyard is not four handbreadths by four handbreadths, if its total area is 16 square handbreadths (e.g., it is is eight cubits by two), the restrictions mentioned in this halachah do not apply. Significantly, the Rashba accepts the more lenient view and, in this instance, the Shulchan Aruch (Orach Chayim 357:1) follows his ruling. on the Sabbath, because [the water] will flow into the public domain rapidly.62Pouring the water into the courtyard does not violate a Torah prohibition, because the courtyard itself is an extension of the home. Although the water flows into the public domain, this is due to the forces of gravity and inertia. Thus, the person's pouring of the water is considered as merely a cause; it is not considered as if he poured the water into the public domain directly. Nevertheless, the Rabbis forbade pouring the water in this manner.
Therefore, it is necessary to dig a pit that contains two seah63A seah is approxinmately 8.25 liters according to Shiurei Torah and 14.4 liters according to the Chazon Ish. The Sages chose this measure because they considered this to be the average quantity of water used by a person every day (the Rambam's Commentary on the Mishnah, Eruvin 8:9). in the courtyard or in the public domain next to the courtyard, so that the water will collect there. [If the pit is within the public domain], one must build a domed covering64Note the Shulchan Aruch (loc. cit.), which differs and mentions a covering of boards, which most likely is flat. over this pit from the outside so that the pit will not be seen in the public domain.65In his Commentary on the Mishnah (op. cit.), the Rambam explains that the covering will cause the pit to be separated from the public domain. (See Shulchan Aruch HaRav 357:1 and the Be'ur Halachah, which explain that because of its dome-like cover, people will not walk over it easily. Hence, since its opening faces the private domain, it is considered to be a hole adjacent to the private domain or a makom patur.) Note the Beit Yosef (Orach Chayim 357) who explains that the reason for the cover is to prevent people's suspicions from being aroused.
The courtyard and the patio adjoining it are combined [when calculating] the four cubits. How large is a pit that contains two seah? [A pit] half a cubit by a half a cubit in area and three fifths of a cubit high.

הלכה יז
הָיְתָה הָעוּקָה פְּחוּתָה מִסָּאתַיִם שׁוֹפְכִין לָהּ בְּמִלּוּאָהּ. הָיְתָה מַחְזֶקֶת סָאתַיִם שׁוֹפְכִין לָהּ אֲפִלּוּ שִׁשִּׁים סְאָה שֶׁל מַיִם. וְאַף עַל פִּי שֶׁהַמַּיִם יִתְגַּבְּרוּ וְיָפוּצוּ מֵעַל הַגּוּמָה לַחוּץ. בַּמֶּה דְּבָרִים אֲמוּרִים בִּימוֹת הַגְּשָׁמִים שֶׁהַחֲצֵרוֹת מִתְקַלְקְלוֹת וּסְתָם צִנּוֹרוֹת מְקַלְּחִין וְלֹא יָבוֹאוּ הָרוֹאִים לוֹמַר שֶׁזֶּה מִשְׁתַּמֵּשׁ בִּרְשׁוּת הָרַבִּים וְהַמַּיִם יוֹצְאִים מִכֹּחוֹ בִּרְשׁוּת הָרַבִּים. אֲבָל בִּימוֹת הַחַמָּה אִם הָיְתָה מַחְזֶקֶת סָאתַיִם אֵין שׁוֹפְכִין לָהּ אֶלָּא סָאתַיִם. הָיְתָה פְּחוּתָה מִסָּאתַיִם אֵין שׁוֹפְכִין לָהּ כָּל עִקָּר:
כסף משנה
17.
If the pit cannot contain two seah, we may pour [no more than] its contents into it. If it can contain two seah, we may pour [any amount of] water into it, even 60 seah, despite the fact that the water will overflow and spill from the pit outward.
When does the above apply? In the rainy season, at which time the courtyards are muddied and many drainpipes spread water. Thus, onlookers will not say that this person is making use of the courtyard and the water is flowing into the courtyard because of his power. In the summer, by contrast, if [the pit] can contain two seah, only that amount may be poured into it. If it cannot contain two seah, no water at all may be poured into it.

הלכה יח
בִּיב שֶׁשּׁוֹפְכִין לוֹ מַיִם וְהֵן נִזְחָלִין וְהוֹלְכִין תַּחַת הַקַּרְקַע וְיוֹצְאִין לִרְשׁוּת הָרַבִּים. וְכֵן צִנּוֹר שֶׁשּׁוֹפְכִין עַל פִּיו מַיִם וְהֵן נִזְחָלִין עַל הַכֹּתֶל וְיוֹרְדִין לִרְשׁוּת הָרַבִּים. אֲפִלּוּ הָיָה אֹרֶךְ הַכֹּתֶל אוֹ אֹרֶךְ הַדֶּרֶךְ שֶׁתַּחַת הָאָרֶץ מֵאָה אַמָּה אָסוּר לִשְׁפֹּךְ עַל פִּי הַבִּיב אוֹ עַל פִּי הַצִּנּוֹר מִפְּנֵי שֶׁהַמַּיִם יוֹצְאִין מִכֹּחוֹ לִרְשׁוּת הָרַבִּים. אֶלָּא שׁוֹפֵךְ חוּץ לַבִּיב וְהֵן יוֹרְדִין לַבִּיב:
כסף משנה
18.
[The following rules apply] to a drain through which water is poured and the water flows under the ground into the public domain, and to a gutter when water is poured over its mouth and the water flows down a wall and descends to the public domain: Even if the wall is 100 cubits long or the stretch of ground under which [the water] passes is 100 cubits long, it is forbidden to pour into the mouth of this drain or this gutter, for because of one's power, the water flows into the public domain. Instead, one should pour outside the drain, [allowing the water to] flow into the drain on its own accord.

הלכה יט
בַּמֶּה דְּבָרִים אֲמוּרִים בִּימוֹת הַחַמָּה אֲבָל בִּימוֹת הַגְּשָׁמִים שׁוֹפֵךְ וְשׁוֹנֶה וְאֵינוֹ נִמְנָע. שֶׁסְּתָם צִנּוֹרוֹת מְקַלְּחִין הֵן וְאָדָם רוֹצֶה שֶׁיִּבָּלְעוּ הַמַּיִם בִּמְקוֹמָן. הָיָה שׁוֹפֵךְ עַל פִּי הַבִּיב וְהַמַּיִם יוֹצְאִין לְכַרְמְלִית הֲרֵי זֶה מֻתָּר וַאֲפִלּוּ בִּימוֹת הַחַמָּה שֶׁלֹּא גָּזְרוּ עַל כֹּחוֹ בְּכַרְמְלִית. לְפִיכָךְ מֻתָּר לִשְׁפֹּךְ עַל כָּתְלֵי הַסְּפִינָה וְהֵם יוֹרְדִין לַיָּם:
כסף משנה
19.
When does the above apply? In the summer. In the winter, by contrast, one may pour [water as mentioned above], and indeed, do so repeatedly, without inhibition. At that time, the gutters are flowing [with water], and a person desires that the water will be absorbed in its place.
The protrusion extending above the sea
[In contrast,] it is permitted for a person to pour water over a drain which flows into the carmelit, even in the summer. No decrees were enacted against [the effect of] a person's power in a carmelit. For this reason, it is permitted to pour [water] down the side of a ship and have it descend to the sea.

הלכה כ
לֹא יְמַלֵּא אָדָם מַיִם מִן הַיָּם וְהוּא בְּתוֹךְ הַסְּפִינָה אֶלָּא אִם כֵּן עָשָׂה מְקוֹם אַרְבָּעָה עַל אַרְבָּעָה יוֹצֵא מִן הַסְּפִינָה עַל הַיָּם. בַּמֶּה דְּבָרִים אֲמוּרִים כְּשֶׁהָיָה תּוֹךְ עֲשָׂרָה אֲבָל אִם הָיָה לְמַעְלָה מֵעֲשָׂרָה מִן הַיָּם מוֹצִיא זִיז כָּל שֶׁהוּא וּמְמַלֵּא. שֶׁהֲרֵי דֶּרֶךְ מְקוֹם פְּטוֹר מְמַלֵּא וְאֵינוֹ צָרִיךְ לְזִיז זֶה אֶלָּא מִשּׁוּם הֶכֵּר:
כסף משנה
20.
A person who is standing in a ship should not draw water from the sea unless he builds a protrusion, four [handbreadths] by four [handbreadths], extending from the ship above the sea.
When does the above apply? When [the deck of the ship] is within ten [handbreadths of the water level]. If, however, [the deck] is more than ten [handbreadths above the water level], he may draw water after erecting a protrusion of the smallest size. [The rationale for this leniency is that] he is drawing water through a makom patur, and the protrusion is necessary only to make a distinction.

הלכה כא
הַקּוֹרֵא בְּסֵפֶר בְּכַרְמְלִית וְנִתְגַּלְגֵּל מִקְצָת הַסֵּפֶר לִרְשׁוּת הָרַבִּים וּמִקְצָתוֹ בְּיָדוֹ. אִם נִתְגַּלְגֵּל לְחוּץ לְאַרְבַּע אַמּוֹת הוֹפְכוֹ עַל הַכְּתָב וּמַנִּיחוֹ. גְּזֵרָה שֶׁמָּא יִשָּׁמֵט כֻּלּוֹ מִיָּדוֹ וְיַעֲבִירֶנּוּ אַרְבַּע אַמּוֹת. נִתְגַּלְגֵּל לְתוֹךְ אַרְבַּע אַמּוֹת גּוֹלְלוֹ אֶצְלוֹ. וְכֵן אִם נִתְגַּלְגֵּל לִרְשׁוּת הַיָּחִיד גּוֹלְלוֹ אֶצְלוֹ. הָיָה קוֹרֵא בִּרְשׁוּת הַיָּחִיד וְנִתְגַּלְגֵּל לִרְשׁוּת הָרַבִּים אִם נָח בָּהּ הוֹפְכוֹ עַל הַכְּתָב. וְאִם לֹא נָח אֶלָּא הָיָה תָּלוּי בַּאֲוִיר רְשׁוּת הָרַבִּים וְלֹא הִגִּיעַ לָאָרֶץ גּוֹלְלוֹ אֶצְלוֹ:
כסף משנה
21.
[The following rules apply when] a person was reading a scroll in a carmelit, a portion of the scroll rolled into the public domain, and a portion remained in his hand: If it rolled more than four cubits, he should turn it face down and leave it. This is a decree, enacted lest [the scroll] drop from his hand and he carry it [more than] four cubits. If it rolled less than four cubits, he should roll it back toward himself. Similarly, if it rolled into a private domain, he should roll it back towards himself.
[The following rules apply when] a person was reading in a private domain and the scroll rolled into a public domain]: If it came to rest, he should turn the scroll face down. If it did not come to rest, but rather remained suspended in the air above the public domain and did not reach the earth, he may roll it back to himself.

הלכה כב
הַמַּעֲבִיר קוֹץ כְּדֵי שֶׁלֹּא יִזּוֹקוּ בּוֹ רַבִּים. אִם הָיָה בִּרְשׁוּת הָרַבִּים מוֹלִיכוֹ פָּחוֹת פָּחוֹת מֵאַרְבַּע אַמּוֹת. וְאִם הָיָה בְּכַרְמְלִית מוֹלִיכוֹ כְּדַרְכּוֹ אֲפִלּוּ מֵאָה אַמָּה. וְכֵן מֵת שֶׁהִסְרִיחַ וְנִתְבַּזָּה יֶתֶר מִדַּאי וְלֹא יָכְלוּ שְׁכֵנִים לַעֲמֹד מוֹצִיאִין אוֹתוֹ מֵרְשׁוּת הַיָּחִיד לְכַרְמְלִית. הַיּוֹרֵד לִרְחֹץ בַּיָּם כְּשֶׁהוּא עוֹלֶה מְנַגֵּב עַצְמוֹ שֶׁמָּא יַעֲבִיר מַיִם שֶׁעָלָיו אַרְבַּע אַמּוֹת בְּכַרְמְלִית:
כסף משנה
22.
A person who moves thorns so that the public at large will not be injured [should adhere to the following guidelines]: If [the thorns] were in the public domain, he should move them less than four cubits at a time. If they were located in a carmelit, he may move them even 100 cubits in a normal manner.
Similarly, if a corpse [began to decompose,] emit foul odors, and become extremely abhorrent to the extent that the neighbors cannot bear to remain [in the same place], it may be taken from a private domain to a carmelit.
After a person descends to bathe in the sea, he should dry himself when he ascends, lest he carry the water that is on him more than four cubits in a carmelit.

זמנים הלכות שבת פרק טו
Zemanim Shabbos Chapter 15