No clapping on Shabbat?

Today's Daf Yomi forbids clapping on Shabbat and Yom Tov. Shabbat 148b quotes a mishnah from Beitsah 36b:

ואמר ליה רבא בר רב חנן לאביי: תנן, לא מספקין ולא מטפחין ולא מרקדין ביום טוב. וקא חזינן דעבדין, ולא אמרינן להו ולא מידי! [...] אלא: הנח לישראל, מוטב שיהו שוגגין ואל יהו מזידין.

It's a straightforward mishnah brought down straightforwardly by the Shulhan Arukh, OH 339:4. No clapping.

But of course, many of us do clap. Many authorities came to acknowledge this over history, starting with this Gemara, and continuing through the rishonim and aharonim.

Rabbi Ari Enkin already goes through the sources on this topic, so I don't have to go through them all here. But some are worth seeing inside.

Lemonade on Shabbat

Shabbat 143b through 145a addresses sehitah, the prohibition against squeezing on Shabbat. This came up on this blog once before.

The posekim debate how this prohibition relates to making lemonade. At first glance, you might think that making lemonade is a straightforward example of squeezing. But God forbid that lemonade should be asur on Shabbat!

First, here are the basics that most rishonim learn from the give-and-take on these pages of Gemara. (It happens to be a relatively challenging give-and-take to follow, which is kind of unfair to Daf Yomi learners on Purim weekend.) There are three type of fruit: grapes and olives, which may not be squeezed mide-orayta; "tutim ve-rimonim," fruits which are commonly squeezed for juice, and may not be squeezed mide-rabbanan; and other fruits, which may be squeezed lekha-tehillah. That's most rishonim, including the Rif, Rambam, Semag and Rosh. and most Rashi, Tosafot, and the Semak are mahmir with that last one, and only allow squeezing a fruit if you do so to sweeten the fruit.

Adjusting a timer on Shabbat

If you're looking for the laws of a timer on Shabbat, click right on through to the article by Rabbi Michael Broyde. This post discusses a related hava amina that caught my interest while learning today's daf.

The Mishnah on Shabbat 29b quotes a dispute about setting up a vessel to drip oil into your lamp:

לֹא יִקֹּב אָדָם שְׁפוֹפֶרֶת שֶׁל בֵּיצָה וִימַלְאֶנָּה שֶׁמֶן וְיִתְּנֶנָּה עַל פִּי הַנֵּר בִּשְׁבִיל שֶׁתְּהֵא מְנַטֶפֶת, אֲפִלּוּ הִיא שֶׁל חֶרֶס. וְרַבִּי יְהוּדָה מַתִּיר. אֲבָל אִם חִבְּרָהּ הַיּוֹצֵר מִתְּחִלָּה, מֻתָּר, מִפְּנֵי שֶׁהוּא כֶלִי אֶחָד.

The explanation of most commentators is that you may come to take the oil from the vessel, and thus violate the prohibition of extinguishing, mekhabbeh. Rashi here:

שתהא מנטפת — ויתקיים הנר, שתהא השמן מטפטף כל שעה לתוך הנר, וטעמא משום גזרה, שמא יסתפק הימנו, וכיון שהקצהו לנר - חייב משום מכבה, ואפילו אותה שפופרת של חרס דמאיסא ליה גזרינן.