ANSWERS TO REVIEW QUESTIONS
prepared by Rabbi Eliezer Chrysler
Kollel Iyun Hadaf, Jerusalem
Previous dafShabbos 20
(a) Meat, onions and eggs must be roasted 'ke'Ma'achal ben Derusai' - one
third of their cooking time.
(b) ben Derusai was an infamous robber who would eat his meat etc. one
(c) This leniency applies to cooking, too.
(d) Food that has been cooked is not subject to 'Bishul Akum', and that
begins from the time the food is cooked 'ke'Ma'achal ben Derusai'.
(a) When Rebbi Eliezer says in our Mishnah that bread may be left in the
oven from the moment that the bottom has crusted, what did he mean by the
bottom, the side that sticks to the wall of the oven, or the outside of the
bread that faces the air?
(b) The Gemara concludes that he is referring to the side that sticks to
the wall of the oven, a Chumra, since it is the outside of the bread, which
faces the flame, that bakes first.
(c) The Gemara only permitted leaving a kid-goat in the oven to roast, when
it has been cut-up, and the air will interfere with the roasting, but not
when the kid is still whole.
(a) We do not suspect that the Kohanim will stoke the coals on Shabbos,
because of the principle 'Kohanim Zerizim Hen'.
(b) "Lo Seva'aru Eish be'Chol Moshvoseichem" comes to teach us, that,
although the Kohanim are not permitted to light the fire in Meduras Beis
ha'Mokad (which is included in 'Moshvosei*chem*' - belonging to the people)
on Shabbos, they *are* permitted (and even obligated) to burn the limbs
that have been left over from the Friday Korban (since this is not included
in 'Moshvosei*chem*' - since the Chalavim are the property of Hashem).
(a) When Rav permits lighting a fire on Erev Shabbos only if the flame has
taken 'be'Rov Kol Echad ve'Echad', he means that the majority of each log
has to be alight.
(b) According to Shmuel, it will suffice if one no longer needs to say
'Bring more wood to place underneath the burning logs' - to ensure that the
fire does not go out.
(c) By a solitary log of wood, some say that one requires the majority of
its thickness to be alight before Shabbos enters, whereas others require
the majority of the circumference. The Gemara therefore concludes, that we
(d) Some interpret "ve'ha'Ach" to mean a willow tree, or willow wood.
Others explain it to mean a pile of burning wood (from the root 'Ach' -
brother, because the one piece burns the other.
(a) When canes have been tied together, the fire has difficulty in igniting
them, and consequently, in spite of their flammability, they require a
majority to be lit before Shabbos.
(b) Similarly, date-pits require a majority, when they are pressed tight in
a box, because then, due to their compactness, the flame cannot get to
(c) Rav Chisda maintains quite the opposite to be true. Under normal
circumstances, according to him, the canes and the pits scatter and will
therefore not ignite each other; whereas if the former is tied and the
latter placed in a box, they *will*.
(d) Rav Kahana agrees with Rav Huna, making it Halachah.
(a) A Madurah is a bonfire. A bonfire of pitch, sulfur, cheese or wax do
not require a majority to be lit before Shabbos, because the fire burns
Hadran Alach, Yetzi'os ha'Shabbos'.
(b) The Beraisa adds straw and stubble to the list.
(c) If a wick dipped in oil (which burns well) requires the majority to be
lit, then how much more so - twigs!
(d) 'Shucha de'Arza' is the woolly substance that is found between the bark
and the trunk of a willow tree. 'Zaza' is moss. Neither requires a
Perek Bameh Madlikin
(a) 'Shucha de'Arza' is the woolly substance between the bark and the trunk
of the tree (as we just learnt at the end of 'Yetzi'os ha'Shabbos).
(b) The Gemara first thought that flax shavings are what the Mishnah calls
'Chosen', which is one of the Pasul wicks listed in our Mishnah. It
concludes however, from a Pasuk in Yeshayah, that flax shavings and Chosen
are two different things, and that, in fact, the former are not fit
(technically - see Tosfos Yeshanim, quoted in the left-hand margin) to use
(c) 'Kisna de'Dayek ve'Lo Nafitz' is flax that has been combed but not
spun, which is why the oil does not run up the wick (although this is not
the reason given by the Gemara later for the Pasul wicks - see 21a, answer
(d) 'Shira'im' is a silk coat. 'Shira Parnada' or 'Gushkera' is a coat made
of the waste of silk.
(a) 'Pesilas ha'Midbar' is the woolly substance found between the bark and
the trunk of a willow tree, that we already explained above (at the end of
Our Tana includes neither wicks made of wool - because the flame jumps, nor
those made of hair - because the fire merely singes them, but does not
create a flame.
(b) 'Pesilas ha'Midbar' is the name of a certain type of tall grass that
grows in the desert.
(c) 'Yerokah she'Al Penei ha'Mayim' is barnacles that one finds growing on
the sides of a ship. It cannot be the moss that floats on the surface of
the water, because that tends to just break up, and is not fit to be used
(d) The reason that the above are all Pasul as wicks, is because they do
not suck up the oil, as good wicks tend to do.
(a) The reason that the Beraisa needed to inform us that, until now, our
Tana has been dealing with Pasul wicks, and that, from now on, he will deal
with Pasul oils (even though this appears obvious), is in order to make it
clear, that although wax is Pasul to be used as an oil, it is not included
in the Pasul wicks - i.e. to use it in the way that we do - in the form of
1. ... 'Zefes' is the pitch.
(c) It is important to know that 'Itran' is another name for 'Pesulta
de'Zifta' and 'Sha'avah', for 'Pesulta de'Duvsha' - for buying and selling
purposes - e.g. that if someone purchases 'Itran' or 'Sha'avah', one may
supply him with 'Pesulta de'Duvsha' or 'Pesulta de'Zifta' , respectively.
2. ... 'Sha'avah' is bee's wax - the waste of honey.
3. ... 'Itran' is the waste of pitch (a liquid that oozes from the wood
(after the pitch has been extracted), when one applies heat.