Reference for Zavim 4:5
עֶשֶׂר טַלִּיּוֹת זוֹ עַל גַּב זוֹ, יָשֵׁן עַל גַּבֵּי הָעֶלְיוֹנָה, כֻּלָּן טְמֵאוֹת. הַזָּב בְּכַף מֹאזְנַיִם וּמִשְׁכָּב וּמוֹשָׁב כְּנֶגְדּוֹ, כָּרַע הַזָּב, טְהוֹרִין. כָּרְעוּ הֵן, טְמֵאִין. רַבִּי שִׁמְעוֹן אוֹמֵר, בִּיחִידִי, טָמֵא. וּבִמְרֻבִּין, טָהוֹר, שֶׁאֵין אֶחָד נוֹשֵׂא אֶת רֻבּוֹ:
Ten cloaks [piled] one on top of the other, [if a <i>zav </i>] slept on the top one, they are all unclean. [If] a <i>zav </i> was on one pan of a balance and [objects fit to] lie or sit on, were on the opposite side [pan], if the <i>zav </i> weighed down [his pan, thus pushing the objects up], they are clean. If it objects weighed down [pushing the <i>zav </i> up] they are unclean. Rabbi Shimon says, [if there was] a single [object to sit or lie on] it is unclean, [but] if there were many, they are clean, since none of them have supported the greater part [of the weight of the <i>zav </i>].