Mishnah Mikvaos 7:5: If there are three log of [drawn] water, and a kortov of wine fell into them, and their appearance is thereby like that of wine, and they [that mixture] fell into a mikveh [containing fewer than forty se'ah], they have not rendered it invalid [as drawn waters, since their appearance is that of wine]. If there are three log of water less one kortov, and a kortov of milk fell into them, and their appearance is thereby [still] like that of water, and they fell into a mikveh, they have not rendered it invalid [since there is still less than three log, of drawn water]. Rabbi Yochanan ben Nuri says: everything follows the appearance.

שְׁלשָׁה לֻגִּין מַיִם, וְנָפַל לְתוֹכָן קֹרְטוֹב יַיִן, וַהֲרֵי מַרְאֵיהֶן כְּמַרְאֵה הַיַּיִן, וְנָפְלוּ לְמִקְוֶה, לֹא פְסָלוּהוּ. שְׁלשָׁה לֻגִּין מַיִם חָסֵר קֹרְטוֹב, וְנָפַל לְתוֹכָן קֹרְטוֹב חָלָב, וַהֲרֵי מַרְאֵיהֶן כְּמַרְאֵה הַמַּיִם, וְנָפְלוּ לְמִקְוֶה, לֹא פְסָלוּהוּ. רַבִּי יוֹחָנָן בֶּן נוּרִי אוֹמֵר, הַכֹּל הוֹלֵךְ אַחַר הַמַּרְאֶה:

Mishnah Mikvaos 7:6: Regarding a mikveh containing precisely forty se'ah, if two people descended and immersed [in it], one after the other, the first is pure, and the second is impure. Rabbi Yehuda says: if the feet of the first were touching the water [while the second was immersing], even the second is pure. If one immersed a thick wool coat [which absorbs a lot of water] in it, and raised it out, if a small part of it is touching the water [and another person then comes and immerses,] he is pure. Regarding a leather pillow or cushion, once one raised their edges out of the water, the water within them is [considered] drawn. What should one do [in such a case]? One should immerse them and raise them out by their undersides.

מִקְוֶה שֶׁיֶּשׁ בּוֹ אַרְבָּעִים סְאָה מְכֻוָּנוֹת, יָרְדוּ שְׁנַיִם וְטָבְלוּ זֶה אַחַר זֶה, הָרִאשׁוֹן טָהוֹר, וְהַשֵּׁנִי טָמֵא. רַבִּי יְהוּדָה אוֹמֵר, אִם הָיוּ רַגְלָיו שֶׁל רִאשׁוֹן נוֹגְעוֹת בַּמַּיִם, אַף הַשֵּׁנִי טָהוֹר. הִטְבִּיל בּוֹ אֶת הַסָּגוֹס וְהֶעֱלָהוּ, מִקְצָתוֹ נוֹגֵעַ בַּמַּיִם, טָהוֹר. הַכַּר וְהַכֶּסֶת שֶׁל עוֹר, כֵּיוָן שֶׁהִגְבִּיהַּ שִׂפְתוֹתֵיהֶם מִן הַמַּיִם, הַמַּיִם שֶׁבְּתוֹכָן שְׁאוּבִין. כֵּיצַד יַעֲשֶׂה, מַטְבִּילָן וּמַעֲלֶה אוֹתָם דֶּרֶךְ שׁוּלֵיהֶם: