Middos, Chapter 5, Mishnah 3. With this mishnah and the one that follows, the masechet draws to a close by cataloguing the chambers of the Beit Hamikdash. It begins with a tally: "Shesh lishakot hayu ba'azarah", the courtyard contained six chambers, "shalosh batzafon", three of them ranged along the north, "veshalosh badarom", and three along the south.
Now, the Beit Hamikdash contained a great many rooms, far more than six. What the mishnah is counting here is a specific category. Three conditions had to be met for a chamber to be included in this list: it had to be built inside the courtyard itself rather than within the thickness of the walls, it had to stand at ground level, and its entrance had to open directly into the azarah.
The Three Chambers in the South
The mishnah turns first to the southern side and names what stood there: "shebadarom", on the south, were "lishkat hamelach", the Chamber of Salt; "lishkat haparvah", the Chamber of Parvah; and "lishkat hamadichim", the Chamber of the Rinsers. Each is then defined by the work that was carried out inside it.
Lishkat Hamelach
The first of them, "lishkat hamelach", held the Mikdash's supply of salt: "sham hayu notnim melach", there the salt was deposited, "lakorban", for use with the offerings. One application of that salt was the preserving of the hides of the korbanot, the process through which a raw skin is made into workable leather.
Lishkat Haparvah
In "lishkat haparvah" the salting itself took place: "sham hayu molchin", there they would salt, "orot kodashim", the hides of consecrated animals, which were the property of the kohanim. Why should such labor be done on Mikdash grounds at all? It forms no part of the service of the korban, and a hide bears no kedushah of its own. The reason is a practical one: had a kohen been obliged to carry his hide home before treating it, the skin would have spoiled along the way and he would have forfeited its value entirely. To spare the kohanim that loss, the work was permitted on site.
The name Parvah is explained in two ways. The Bartenura records a tradition that a magician called Parvah erected this chamber through his magic arts, and it retained his name ever after. The Rambam preserves a different account: Parvah was a man who contrived to enter the Mikdash unnoticed in order to watch the Kohen Gadol perform the Yom Kippur service with the ketoret. His scheme came to light, and he met his end in that very chamber.
"Ve'al gagah", and upon its roof, "hayah beit hatvilah", there was a place of immersion, "leKohen beYom HaKippurim", for the Kohen Gadol on Yom Kippur. The avodah of that day obliges him to immerse several times, and the majority of those immersions were performed at this spot.
Lishkat Hamadichim
The third room is "lishkat hamadichim": "shesham hayu madichim", for there they would wash, "kirvei hakodashim", the entrails of consecrated animals, in preparation for bringing them up onto the mizbeach. Because the stomachs were packed with refuse, a room of its own was designated for the job, keeping the other portions of the korban from being soiled. The rest of the innards, which were considerably cleaner, were washed at the marble tables that stood in the courtyard, as we have already seen.
The Spiral Staircase
"Umisham mesibah olah", and from there a winding stairway climbed, "legag beit haparvah", up to the roof of the Parvah chamber, where the mikveh stood. Note where the stairs began: not in Parvah, but in the adjoining chamber, sparing the Kohen Gadol the stench of the salting room as he made his way up to immerse. The stairwell was covered over as well, both so that the rinsing chamber would remain hidden from view and so that the kohanim, the Kohen Gadol above all, would not be watched as they went up to the mikveh.