I am going through this Mesechet, and I am just puzzled by the turn of events. the Mishnah goes from dealing with what may be carried out Shabbat, to the subject of Tumah. Can you help me understand why this subject is in this Mesechet, and not somewhere else.
Nechemyah D, Riverside, USA
Tosfos DH Amar on Shabbos 82a (also brought by the Bartenura on Mishnayos) explains that the last Mishnah of Perek 8 which discusses Shi'urim of carrying brings a Pasuk in Yeshaya 30 concerning pottery. The first Mishnah in the next Perek brings the second half of the same Pasuk for a Halachah of Tum'ah, in the same form of Minayin etc. We find other places that the Mishnah goes off on a sidetrack - see Megilah Perek 1 where many Mishnayos begin Ein Bein. On Daf 89b the Mishnah continues with carrying on Shabbos. Perhaps this was a way of remembering Mishnayos with the same structure.
The Bartenura also brings a second explanation. Since there is a Mishnah brought on 86a concerning Shabbos - about heating water for a baby after a Bris which starts Minayin and brings a Pasuk - so too a whole group of Mishnayos which begin Minayin are brought. (This doesn't explain why the whole subject is here in the middle of carrying.)
All the best,