THOUGHTS ON THE DAILY DAF
brought to you by Kollel Iyun Hadaf of Har Nof
Rosh Kollel: Rav Mordecai Kornfeld
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1) HEATING AN EGG IN SAND HEATED BY THE SUN
QUESTION: In the Mishnah (38b), the Tana Kama forbids heating an egg by
breaking it over a cloth that was heated by the sun. Rebbi Yosi argues and
permits it. He agrees, however, that one may not heat an egg by placing it
into sand that was heated by the sun. The Gemara asks why Rebbi Yosi agrees
in the latter case, if he maintains that it is permissible to do Hatmanah
in material that was heated by the sun.
Rabah answers that Rebbi Yosi prohibits putting an egg in sun-heated sand
is because of a decree that one might then think that it is also
permissible to do Hatmanah in ashes in which their are coals, which one
might then stoke in order to increase their heat. Rav Yosef answers that it
is prohibited because one might move dirt in order to bury the egg in the
The Gemara makes it clear that the one who says that the decree was because
of the fear that one might move dirt is not concerned that one might come
to do Hatmanah in ashes.
(a) Why not? He is putting the egg into a material that adds heat, which is
forbidden on Shabbos (the Rabanan made a Gezeirah, lest one do Hatmanah in
ashes with coal and stoke the coal, Shabbos 34b)!
(b) Second, even if the sand would have been a material that does not add
heat, the Halachah is that Hatmanah in material that does not add heat is
forbidden *on Shabbos itself* (see Insights 34:1)!
(a) TOSFOS (DH Ela) answers that the Gezeirah against doing Hatmanah in a
material that adds heat (lest one come to do Hatmanah in hot ashes and
then, on Shabbos, stoke the coals) applies only on Friday, before Shabbos.
*This* Gezeirah does *not* apply on Shabbos, because there is no fear that
one will do Hatmanah in hot ashes, and thereby cook uncooked food, on
(b) TOSFOS (ibid.) answers the second question by pointing out that the
Gezeirah not to do Hatmanah on Shabbos lest one attempt to bring the food
to a boil, applies only to something that is already cooked. That is,
normally one insulates a food that is already cooked in order to preserve
its heat; we are afraid that he might unexpectedly find that his food is
cold when it should be hot, and he will heat it up, forgetting that it is
Shabbos. In our situation, though, the person not only *knows* that his
food is cold, he knows that it is *not even cooked*. We are not afraid that
he will attempt to cook it from scratch (using fire) on Shabbos.
2) DOING "HATMANAH" IN MATERIAL THAT ADDS HEAT
QUESTION: Rav Chisda says that we learn from the incident with the people
of Tiberias that it is prohibited to do Hatmanah in material that adds
heat. Why does he say that we learn this from the incident with the people
of Tiberias? The Mishnah (47b) states this Halachah explicitly!
(a) TOSFOS (DH me'Ma'aseh) answers that without the incident in Tiberias,
we might have thought that the Mishnah later is only prohibiting Hatmanah
during *Bein ha'Shemashos*, but while it is still day on Friday Hatmanah is
permissible. Therefore, we need the incident in Tiberias to teach us that
even on Friday before Shabbos, it is prohibited to do Hatmanah in material
that adds heat.
(b) TOSFOS (ibid.) gives another answer. If we only had the Mishnah later,
we might have thought that it is only prohibited to do Hatmanah to begin
with, but *b'Di'eved*, if one did Hatmanah, the food is permitted. The
incident in Tiberias teaches us that the food itself is also prohibited.
(c) RAV YONAH cited in Tosfos (ibid.) answers that the incident in Tiberias
teaches us that one may not do Hatmanah in material that adds heat even
with a *raw* food. Even though leaving a raw food on the stove (Shehiyah)
on Friday is permitted, doing Hatmanah with a raw food is forbidden.
(d) The RITVA, RAMBAN, and RASHBA explain that the Halachah stated in the
Mishnah on 47b was said as a *result* of the incident in Tiberias. It was
in Tiberias, during the episode described in our Mishnah (38b), that the
Chachamim first said that Hatmanah in material that adds heat is