The fire-basket of a householder which was lessened by less than three handbreadths is susceptible to impurity because when it is heated from below a pot above would still boil. If [it was lessened] to a lower depth it is not susceptible to impurity. If subsequently a stone or gravel was put into it, it is still not susceptible to impurity. If it was plastered over with clay, it may contract impurity from that point and onwards. This was Rabbi Judah's reply in connection with the oven that was placed over the mouth of a cistern or over that of a cellar.

A double stove which was split into two parts along its length is clean. Through its breadth is unclean. A single stove which was split into two parts, by its length or by its width, it is not susceptible to impurity. As to the extension around a stove, whenever it is three fingerbreadths high it contracts impurity by contact and also through its air-space, but if it is less it contracts impurity through contact and not through its air- space. How is the air-space determined? Rabbi Ishmael says: He puts a spit from above to below and opposite it contracts impurity through the air-space. Rabbi Eliezer ben Jacob says: if the stove contracted impurity the extension is also unclean, but if the fender contracts impurity the stove does not become unclean.

If it [the extension] was detached from the stove, whenever it was three fingerbreadths high it contracts impurity by contact and through its air-space, If it was lower or if it was smooth it is clean. If three props on a stove were three fingerbreadths high, they contract impurity by contact and through their air-space. If they were lower, all the more so they contract impurity, even where they were four in number.

If one of them [i.e. the props] was removed, the remaining ones contract impurity by contact but not through air-space, the words of Rabbi Meir. Rabbi Shimon says that they are clean. If originally he made two props, one opposite the other, they contract impurity by contact and through air-space; the words of Rabbi Meir. Rabbi Shimon says that they are clean. If they were more than three fingerbreadths high, the parts that are three fingerbreadths high and below contract impurity by contact and through air-space but the parts that are more than three fingerbreadths high contract impurity by contact and not through air-space; the words of Rabbi Meir. Rabbi Shimon says that they are clean. If they were withdrawn from the rim [of the stove], the parts which are within three fingerbreadths contract impurity by contact and through air-space, and those parts that are removed more than three fingerbreadths contract impurity by contact but not through air-space, the words of Rabbi Meir. Rabbi Shimon says that they are clean.

How do we measure them? Rabban Shimon ben Gamaliel says: he puts the measuring-rod between them, and any part that is outside the measuring-rod is clean while any part inside the measuring-rod, including the place of the measuring-rod itself, is unclean.