Shabbat 41 - Shabbat swim
Rav Zeira said, "I have observed Rabbi Abahu in a pool, but I still don’t know if he swam or not." What was Rav Zeira’s problem? The Sages forbade swimming in lakes and rivers on Shabbat, lest one come to make a flotation device, and this refers even to pools!? Rav Zeira did not know if this refers to pools without embankments, which are more similar to lakes, or even to pools with embankments. The Talmud discusses two more instances of Rav Abbahu’s behavior about which Rav Zeira was not sure.
When Rav Zeira was planning to go live in Israel, he avoided Rav Yehudah, because Rav Yehudah forbade leaving the Diaspora and moving to Israel, until God makes it so. His reason was the phrase from prophet Jeremiah, " I will bring you to Babylon, and there you will stay ". However, as Rav Zeira craved the teachings of Rav Yehudah, he sneaked to listen from behind the bathhouse, where he heard Rav Yehudah say in Hebrew, "Please bring me soap and a brush," and then continue in Aramaic, talking to his attendants, "Drink some of the hot water of the bathtub." Rav Zeira deduced from here that one is permitted to talk about daily matters in Hebrew in a bathtub, and that it is beneficial to drink hot liquid while in a bathtub. Incidentally, one who leaves the bathtub and does not rinse himself in cold water is similar to metal that has been heated but not put into cold water for hardening. Rav Zeira then said, "Had I come to hear only these things, it would be enough." Some say, he meant, "Had I only been born."
One can drink hot water from a samovar from which hot coals have been removed - if the coals are on the inside of the samovar. However, if its coals are in a large compartment on the outer sides of the samovar, then this compartment keeps adding heat throughout Shabbat, and drinking this water is forbidden.
Art: Petrov-Vodkin - "Still life with samovar"