If he put three props into the ground and joined them [to the ground] with clay so that a pot could be set on them, [the structure] is susceptible to impurity. If he set three nails in the ground so that a pot could be set on them, even though a place was made on the top for the pot to rest, [the structure] is not susceptible to impurity. One who made a stove of two stones, joining them [to the ground] with clay: It is susceptible to impurity. Rabbi Judah says that it is not susceptible to impurity, unless a third stone is added or [the structure] is placed near a wall. If one stone was joined with clay and the other was not joined with clay, [the structure] is not susceptible to impurity.

A stone on which he placed a pot, [on it] and on an oven, or on it and a double stove, or on it and on a stove, is susceptible to impurity. [If he set the pot] on it and on another stone, on it and on a rock, or on it and on a wall, it is not susceptible to impurity. And such was the stove of the Nazirites in Jerusalem which was set up against a rock. As regards the stove of the butchers, where the stones are placed side by side, if one of the stoves contracted impurity, the others do not become unclean.

If one made two stoves of three stones and one of the outer ones was defiled the half of the middle one that serves the unclean one is unclean but the half of it that serves the clean one remains clean. If the clean one was removed, the middle one is regarded as completely transferred to the unclean one. If the unclean one was removed, the middle one is regarded as completely transferred to the clean one. Should the two outer ones become defiled, if the middle stone was large, each outer stone is allowed such a part of it as suffices for the support of a pot and the remainder is clean. But if it was small all of it is unclean. Should the middle stone be removed, if a big kettle can be set on the two outer stones they are unclean. If the middle stone is returned they all become clean again. If it was plastered with clay it becomes susceptible to impurity when it is heated to a degree that suffices for the cooking of an egg.