As we learned on yesterday’s daf Beit Hillel and Beit Shammai disagree whether a person’s objects can perform work on his behalf on Shabbat. The halakha follows the opinion of Beit Hillel who permit beginning an action on Friday afternoon that is prohibited on Shabbat, even if will continue into Shabbat itself. The Gemara on today’s daf continues the discussion of this type of activity.
The Sages taught in a Tosefta: One may open a canal that passes adjacent to a garden on Shabbat eve at nightfall, so that water will flow into a garden and the garden continuously fills with water all day long on Shabbat. Similarly, one may place incense, perfumed herbs placed on coals to produce a fragrance, on coals beneath the clothes on Shabbat eve and the clothes may be continuously perfumed all day long. And, similarly, one may place sulfur beneath the silver vessels on Shabbat eve at nightfall for the purpose of coloring the vessels, and they may be continuously exposed to sulfur all day long.
Throughout the generations, sulfur was used to beautify silver vessels. Since silver is a light hue and engravings are not easily visible, one manner to accentuate the inscriptions was by means of sulfur. The silver vessels were exposed to sulfur fumes and oxidized sulfur, creating a thin layer of black silver sulfate on the vessel. After the vessel was treated with sulfur, it was thoroughly cleaned, restoring all of the surfaces to their original silver sheen while the recesses and sunken areas remained black. In modern times, similar methods are employed.
The ruling that follows Beit Hillel notwithstanding, the Tosefta forbids placing wheat kernels into a water mill unless he does so in a way so that they will be ground while it is still dayon Friday and not on Shabbat. Rabbah explains that the source for this prohibition is rabbinic prohibition – since the mill makes noise and people will hear the noisy mill working on Shabbat. (The reason that the Gemara spoke specifically of a water mill is because a mill powered by an animal is certainly prohibited on Shabbat, due to the mitzva explicitly stated in the Torah to rest one’s animal.)