Keilim, Chapter 27, Mishnah 6. This chapter deals with the minimum measurements that a piece of cloth or leather must have in order to receive tum'ah, and in particular the special measurement needed for tum'at midras, the tum'ah that a zav or a nidah conveys to something they sit or tread upon. The previous mishnah taught a fundamental point about a garment made of two layers: when we measure the shirt of a newborn, the required amount must be present in both the front and the back. It does not suffice that one side has the minimum size. Our mishnah continues along the same line and lists further items that are measured in this doubled fashion.
The Mishnah opens: "Eilu nimdadin kefulim," these are the items that are measured while doubled. The list follows:
- Ampalya - a boot or shoe made of cloth or of leather.
- Pamlinya - a short garment worn on the lower body, reaching from the waist down to the knees.
- Michnasayim - trousers.
- Kova - a hat.
- Kis shel punda - a belt made hollow so that money can be carried inside it.
What unites all of these? Each one of them is constructed of two facing layers, so that the object has two distinct sides. Since the item is fashioned that way, the law requires the minimum shiur to be present in each of the two sides. If only one side has the necessary amount, the object does not become susceptible to tum'at midras. To take a concrete example: if the item is made of cloth, whose shiur for midras is three tefachim by three tefachim, then each of the two sides needs its own three by three, so that between them we are speaking of six tefachim by three tefachim.
Now the Mishnah moves on to a separate case: "u'matlit shetluyah al hasafah." The reference is to a small piece of fabric hanging along the rim of the collar, the opening through which the head passes when the garment is put on. Such a strip would be fastened there as reinforcement, so that the collar would not rip from constant pulling and wear. Whether it is measured singly or doubled depends entirely on the manner in which it was fixed to the garment.
"Im peshutah, nimdedet peshutah" - if the patch lies flat, spread out along one side of the opening, it is measured as it lies, flat and unfolded. If in that spread out state it has the required size, it can become tamei. "Ve'im kefulah, nimdedet kefulah" - but if the patch was folded over the edge, so that part of it lies on the outside of the garment and part of it on the inside, it is measured as a doubled item. In that case each of the two sides must have the minimum shiur on its own; otherwise the patch does not become susceptible to tum'ah.
The principle emerging from this mishnah is straightforward and worth holding on to: when a piece of material is shaped or attached in a way that gives it two sides, the Torah's measurement is not satisfied by adding the sides together. Each layer is looked at as its own surface, and each must reach the shiur before the item can receive tum'ah.