- צירוף כלי of two halves of a minchah (re: tumah and kemitzah)
Rav Kahana answered several questions asked by Rebbe Chiya’s sons about צירוף כלי – a vessel’s ability to combine hekdesh items inside it. If two halves of an עשרון of a minchah were placed into the ביסא – bowl, and a טבול יום touched one half, the other half is also disqualified, because כלי מצרף מה שבתוכו לקדש – a כלי [שרת] combines what is inside it regarding hekdesh, even though the two halves are not touching. If a third half-עשרון was placed between them, and a טבול יום touched it, the other two halves are not disqualified, because a כלי only combines צריך לכלי – [something] which needs the כלי, whereas this third half-עשרון is not part of the minchah. If the טבול יום stuck his finger in the airspace between the two halves, they are not disqualified, because only a כלי חרס is metamei through airspace. Rav Kahana then asked Rebbe Chiya’s sons: מהו לקמוץ מזה על זה – what is the halachah about doing kemitzah for [one] half-עשרון for [the other]? צירוף דאורייתא או דרבנן – Is the halachah of combination Biblical, so the two halves are considered touching even for a leniency, to allow a kemitzah of one for the other, or is it only Rabbinic, and only a stringency?
- שבע לה טומאה
Rava asked: if an עשרון was divided, and one half became tamei, and they were then placed into the ביסא, and then a טבול יום touched the tamei half, does the tahor half become tamei through צירוף כלי? Do we say שבע לה טומאה – [the flour] is already satiated with tumah, and the second event of tumah does not affect it (and cannot be extended to the other half with צירוף כלי), or not? [The original tumah definitely does not spread to the other half, since they were not together when the tumah was contracted] The Gemara proceeds to clarify that a more stringent tumah definitely takes effect on a less stringent one. Thus, a sheet which was tamei from מגע מדרס – touched by a midras, can then become a full מדרס (if a זב sits on it), and if it loses its מדרס status (by being made into a curtain, which is not designed for sitting on), it will revert to its former מגע מדרס tumah. Also, if two טומאות are conveyed simultaneously, both take effect.
- צירוף between a lost half-עשרון, its replacement, and the original other half
Rava discusses a divided עשרון, where one half was lost and another was designated in its place, and the first was found. All three halves were together in the ביסא, and one became tamei: if the אבוד – lost one contracted tumah, then it and the "ראשון" – first half (which was never lost) “combine” to become tamei, but not the מופרש – the designated [replacement], which was never intended to be one minchah with the אבוד. Similarly, if the מופרש contracted tumah, it and the ראשון are tamei, but not the אבוד. However, if the ראשון contracts tumah, then all three halves are tamei, since both other halves were designated to be a minchah with it. Abaye says that no matter which half contracted tumah, all three halves become tamei, because כולהו בני ביקתא דהדדי נינהו – they are all members of the same house, i.e., they all belong to one minchah. They have a parallel machlokes regarding kemitzah: Rava says if he took kemitzah from the אבוד, or from the מופרש, then the שירים from it and the ראשון are permitted, but not from the third half. If he took kemitzah from the ראשון, neither of the others can be eaten (since kemitzah can only permit one other half, which cannot be determined). Abaye says that regardless which half he took kemitzah from, neither of the others can be eaten, since they are all "בני ביקתא דהדדי".