Shabbos, Chapter 8, Mishnah 3. We continue the discussion of the minimum measures established for items of significance, for which one becomes liable when carrying them out on Shabbos.
Leather - enough to make an amulet:
The measure of leather for liability in carrying out is "kedei la'asos kamei'a" - enough to make an amulet. The word "la'asos" (to make) refers here to covering: an amount of leather sufficient to cover an amulet.
Amulets were kabbalistic remedies, sometimes made from various plants and sometimes consisting of particular formulas that were written out, and they were covered with a piece of leather. It is interesting to note that the writing of amulets is still practiced among certain people to this very day. The very same account has been reported by two independent sources: during the years of World War II there was a rabbi in Brooklyn who wrote amulets for protection, and young men together with their mothers stood in line down the street waiting to come in to him before leaving for the front. For one of the young men the amulet was meant to ensure that he would return safely to the rabbi, and it was apparently covered in leather; the second was intended for protection alone, and that man kept it with him for practically his entire life.
The remaining measures in the Mishnah:
"Klaf" - parchment; the measure is enough to write on it the shortest of the passages of the tefillin, the passage of "Shema Yisrael... ve'ahavta," which is the shortest of them all. It is sufficient that the parchment be large enough for that passage to be written on it.
"Deyo" - the ink with which tefillin, mezuzos, a Sefer Torah and the like are written; its measure is the amount needed to write two letters.
"Kachol" - a type of eye makeup; the measure is enough to paint one eye, that is, the amount sufficient to color a single eye only.
And why was the measure set at only one eye? Because in the time of the Mishnah there were exceptionally modest women who would cover one of their eyes and leave the other uncovered, and therefore they would take the trouble to paint only the eye that was visible. This, then, is the measure of kachol for which one who carries it out on Shabbos is liable: the amount needed to color one eye or to add color to it.
In summary: This Mishnah lists further measures of liability for carrying out on Shabbos: leather - enough to cover an amulet; parchment - enough to write on it the shortest passage of the tefillin, the passage of "Shema"; ink - enough to write two letters; and kachol - enough to paint one eye.