Beitza 34 - 40
Shall We Dance?!
You are at a sheva berachot meal on a Shabbat or holiday and everyone is singing to bring joy to the chatan and kallah. Now you see them get up to dance and you are drawn to join them. Then you recall that you learned in the mishna that our Sages prohibited dancing and clapping hands on these holy days. So why are all these truly observant Jews doing so?
But you then try to recollect what the gemara states as the reason for this ban. If dancing and clapping hands will be permitted, say our Sages, one may be drawn into making musical instruments to supply the music which enhances such activities.
Now you have the key to the behavior of your dancing friends. Tosefot (Beitza 30a) explains that this decree was applicable in Talmudic times when many people had the expertise of making musical instruments. In our days, however, when such expertise is uncommon, there is no prohibition on dancing and clapping.
Rema in Shulchan Aruch Orach Chaim 339:3 cites Tosefot's lenient opinion. However, the author of the Shulchan Aruch, the Beit Yosef, only quotes the mishnaic ban, with no mention of it not applying to our times. Therefore, some authorities discourage relying on Tosefot's lenient opinion except when such dancing is for a mitzvah purpose, such as in the case at hand (Mishna Berura 339:10).
Halachic authorities throughout the last centuries have gone to great pains to point out that even for the sake of a mitzvah it is forbidden to play a musical instrument on Shabbat, and certainly to conduct any form of dancing involving men and women together. (See Biur Halacha, ibid, and Iggrot Moshe, Orach Chaim 2:100.)
A Saga of Two Salts
Sodom-salt is a mysterious ingredient which keeps popping up throughout the Talmud. In Mesechta Chulin (105b) it is described as a salt which can cause blindness if it contacts the eyes. This is why we wash our fingers before saying the blessings after a meal.
Rashi here describes this salt as being very thin and therefore capable of clinging to the fingers without being detected. Our gemara distinguishes between two kinds of salt regarding whether they become part of the food they flavor (and thus can be carried on the holiday only as far as the food can). Rashi concludes that the one which is considered assimilated is the thinner, more soluble Sodom-salt. (Maharim Shif points out that this apparently contradicts Rashi's commentary in Bava Batra (20b) where he describes Sodom-salt as "thick and hard as a rock.")
The salt with which Sodom-salt is contrasted both here and in Bava Batra is Astrokhanite salt. This name - explains the early Talmudic dictionary-type commentary Rabbi Natan the "Aruch" - is based on the area where this salt is found. Rashash suggests that this area is Astokhan (near the Asian part of Russia where the Volga River flows into the Caspian Sea) whose salt is distributed throughout Russia by way of the Volga River.