Kelim, Chapter Six, Mishnah One
Today’s mishnah deals with the purity of makeshift stoves.
1) 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.
2) 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.
3) One who made a stove of two stones, joining them [to the ground] with clay:
a) It is susceptible to impurity.
b) Rabbi Judah says that it is not susceptible to impurity, unless a third stone is added or [the structure] is placed near a wall.
4) If one stone was joined with clay and the other was not joined with clay, [the structure] is not susceptible to impurity.
Section one: The props used to make this stove are of earthenware. If he set three of them together so that he could rest a stove on top of them and attached them to the ground with clay, the structure is susceptible to impurity.
Section two: The nails are made of metal and metal that is attached to the ground is not susceptible to impurity. Therefore this structure remains pure even if he makes a place on top out of earthenware for a pot to sit on. The fact that it is covered with some earthenware does not affect its status.
Section three: According to the first opinion, since the stones are wide enough to support the pot, once they are attached with clay to the ground they are considered a stove and they are susceptible to impurity. However, Rabbi Judah retains the rule that we need a tri-partite structure in order to be susceptible to impurity. Therefore, he must either add a third stone or put the structure next to the wall to serve as a third stone.
Section four: According to the sages both stones must be attached to the ground for it to be susceptible to impurity. If one was attached to the ground with clay and the other was not, the structure is not susceptible.