Shabbat 28 – Wick made of wood

Any material that comes from a tree should not a be used to make a wick for the Shabbat lamp, since it does not draw oil well – with the exception of flax. Incidentally, materials coming from a tree, if used to construct a roof over a dead body, do not themselves become ritually impure – again, with the exception of flax.

This terse rule can be explained as follows. Ordinarily, flax is not considered wood, but it is called “wood” once, in the book of Joshua, “And she brought them up to the roof and hid them in the trees of flax...”. Since flax can be used for a wick, and since it does accept ritual impurity, it had to be mentioned and excluded.

The law of the wooden roof not accepting ritual impurity of the dead – although it transmits this impurity to other objects – is derived from the laws of the covering of the Tabernacle. A related question is the skin of an animal called “tachash,” also translated as “blue processed skin” – was it a kosher animal or not. It had one horn, and therefore should have been kosher, since we learned in the tractate Niddah that this is a sign of a kosher animal. Besides, the ox that Adam brought as a sacrifice, also had one horn, and it definitely was kosher. However, it could be that the unicorn called tachash was a special creature that appeared just once, to provide skins for the Tabernacle (it was multicolored, “ joyous in his colors” in Aramaic), but then was hidden again, and its kosher status remains in doubt.

Art: Raphael - The Woman with the Unicorn