Commentary for Mikvaot 6:4
הַסְּפוֹג וְהַדְּלִי שֶׁהָיוּ בָהֶן שְׁלשָׁה לֻגִּין מַיִם וְנָפְלוּ לַמִּקְוֶה, לֹא פְסָלוּהוּ, שֶׁלֹּא אָמְרוּ אֶלָּא שְׁלשָׁה לֻגִּין שֶׁנָּפְלוּ:
Regarding a sponge or a bucket which had inside them three <i>log</i> [a specific unit of liquid measurement] of [drawn] water, if they fell into a <i>mikvah</i> [which does not contain forty <i>se'ah</i> of valid water], they do not render it invalid, for they [the Sages] only said "three <i>log</i> that fell" [into a incomplete <i>mikveh</i> invalidate it; but in these cases, not all of the three log of water actually ever fell into the <i>mikveh</i>, since some remain inside the sponge or bucket].
Bartenura on Mishnah Mikvaot
שהיו בהן שלשה לוגין מים – absorbed and attached to them (i.e., the sponge and/or the bucket), but they are not apparent to the eye, therefore, the Rabbis did not decree that this is not called “that they fell.”
Ask RabbiBookmarkShareCopy
English Explanation of Mishnah Mikvaot
If a sponge or a bucket containing three logs of water fell into a mikveh, they do not make it invalid, because they have only said: "if three logs fell in." This mishnah is a great example of how some later rabbis read and expound upon statements made by earlier sages. The earlier sages said that if three logs of drawn water fall into a mikveh that doesn't have forty logs of water, they render it invalid. The rabbis of our mishnah say that there must be three actual logs of water that fall into the mikveh, not a sponge or a bucket containing three logs of water. Note that the mouth of the bucket must be thinner than the tube of a water-skin. If not, we are in the situation in mishnah two of this chapter and we consider the two sources to be joined.
Ask RabbiBookmarkShareCopy