Kelim, Chapter Twenty-Five, Mishnah Five
This mishnah continues to discuss the measuring vessel that has two sidesone of a quarter log and one of a half-quarter.
1) If the [inside of the] quarter contracted uncleanness, the quarter and its outer side are unclean, but the half quarter and its outer side remain clean.
2) If the [inside of the] half quarter contracted uncleanness, the half quarter and its outer side are unclean, but the quarter and its outer side remain clean.
3) If the outer side of the quarter contracted uncleanness,the outer side of the half quarter remains clean, the words of Rabbi Meir.
a) But the sages say: the outer side cannot be divided.
4) When he immerses the vessel, he must immerse the whole thing.
Section one: Having determined in yesterday’s mishnah that each vessel is independent, the mishnah now deals with the thorny issue of their shared wall.
If the inside of the quarter log became unclean, its own outer side is also unclean. However, the walls of the vessel that surround the half-quarter measuring cup remain clean.
Section two: The same rules apply if the inside of the half-quarter vessel become unclean.
Section three: According to Rabbi Meir, if the outer wall of the quarter vessel becomes unclean, only this outer wall is unclean. The outer wall of the half-quarter remains clean. In other words, although this wall surrounds the entire vessel, we look at it as if it were divided in half and only the part that surrounds the quarter is unclean.
The other sages disagree and say that you can’t divide the wall of a vessel in half. So if the outer wall of either side becomes unclean, both outer walls are considered unclean.
Section four: Despite the fact that it is possible for one side to be clean and the other to be unclean, when he immerses the vessel, he must immerse both sides. If he does not do so, the vessel remains unclean. Note that this is similar to the end of mishnah three.