Commentary for Bava Batra 2:1
לֹא יַחְפֹּר אָדָם בּוֹר סָמוּךְ לְבוֹרוֹ שֶׁל חֲבֵרוֹ, וְלֹא שִׁיחַ, וְלֹא מְעָרָה, וְלֹא אַמַּת הַמַּיִם, וְלֹא נִבְרֶכֶת כּוֹבְסִין, אֶלָּא אִם כֵּן הִרְחִיק מִכֹּתֶל חֲבֵרוֹ שְׁלשָׁה טְפָחִים, וְסָד בְּסִיד. מַרְחִיקִין אֶת הַגֶּפֶת וְאֶת הַזֶּבֶל וְאֶת הַמֶּלַח וְאֶת הַסִּיד וְאֶת הַסְּלָעִים מִכָּתְלוֹ שֶׁל חֲבֵרוֹ שְׁלשָׁה טְפָחִים, וְסָד בְּסִיד. מַרְחִיקִין אֶת הַזְּרָעִים, וְאֶת הַמַּחֲרֵשָׁה, וְאֶת מֵי רַגְלַיִם מִן הַכֹּתֶל שְׁלשָׁה טְפָחִים. וּמַרְחִיקִין אֶת הָרֵחַיִם שְׁלשָׁה מִן הַשֶּׁכֶב, שֶׁהֵן אַרְבָּעָה מִן הָרָכֶב. וְאֶת הַתַּנוּר, שְׁלשָׁה מִן הַכִּלְיָא, שֶׁהֵן אַרְבָּעָה מִן הַשָּׂפָה:
One may not dig a bor [(round)] near his neighbor's bor, nor a shiach [(long and narrow)], nor a ma'arah [(roofed)], nor a water canal, nor a wash-pond [a square pit in which rain water is collected for washing clothes], unless he distances it three handbreadths from his neighbor's wall [i.e., from the wall of his hole. And the thickness of the wall of a hole is not less than three handbreadths, so that the distance from his hole to that of his neighbor is found to be six handbreadths. And one may not place one of the "damagers" alongside his neighbor's boundary unless he removes it the required distance, even if there is no wall there, lest his neighbor decide to build there and he cause damage to him.] And he coats [the walls of his hole] with lime. One distances olive-peel peat, and manure, and salt, and lime, and flint three handbreadths from his neighbor's wall. [For all of these "undermine" a wall. (The "wall" here is not that of a hole.)] One distances sowing, plowing, and urine three handbreadths from a wall. [("plowing":) Plowing even without sowing (as when one plows for trees) undermines a wall. ("urine"): It erodes bricks, which are of dried clay. Therefore, if one urinates near a brick wall, he must move back three handbreadths. With a stone wall, one handbreadth suffices; and with hard stone, such as granite, he need not move back at all.] And a mill must be removed (from a wall). [(Its "rattling" undermines the wall's foundation)] three (handbreadths) from the shechev (the lower part), which are four from the rechev (the upper part). [The rechev "rides" on the shechev, and is a handbreadth narrower.] And an oven (must be removed) three from the kilya which are four from the surface. [The kilya is the base, built of clay and stones, on which the oven is placed. It is broad below and narrow above. The upper surface of the kilya, on which the oven is set, is of the same width as the oven. This base must be removed three handbreadths from the wall, four handbreadths from its upper surface, for the heat of the stove damages the wall.]
Bartenura on Mishnah Bava Batra
English Explanation of Mishnah Bava Batra
Nor may he dig a ditch, cave, water-channel, or laundry pool unless it is three handbreadths away from his fellow’s wall, and he must plaster it with lime.
They distance piles of olive refuse, manure, salt, lime or stones three handbreadths from his fellow’s wall, and he plasters it with lime.
They distance seeds, and a plow and urine three handbreadths from the wall.
And they distance the mill [from the wall]: three [handbreadths] from the lower millstone and four [handbreadths] from the upper millstone.
And [they distance] the oven [from the wall]: three from the belly of the oven and four from the rim of the oven.
Most of the second chapter of Bava Batra deals with the obligations to distance damaging things from another person’s property. Mishnah one deals with distancing things from a person’s wall lest they damage the wall.
Section one states that a person should not dig a cistern close to another person’s cistern since one cistern may cause the other to break. A cistern is where they would store collected rain water, as opposed to a well which collects water from underground.
The remainder of the mishnah deals with distancing things from another person’s wall, lest they cause damage to the wall. The items mentioned in section two may cause the wall to fall, therefore he must distance them three handbreadths and plaster them to prevent water from seeping out.
The items mentioned in section three also may cause damage to another person’s wall and therefore he must distance them and plaster the place in which he places them.
Section four deals with three more items which also must be kept three handbreadths away from another person’s wall: seeds, a plow and urine. The difference between these items and those mentioned previously is that plastering is not applicable in these cases.
Sections five and six mention large items, a mill and an oven which also must be distanced from another’s wall. In both of these cases there are different measurements given for different parts of the item.