Reference for Eruvin 173:11
<big><strong>גמ׳</strong></big> תנו רבנן עשו לה בכניסה ולא עשו לה ביציאה עשו לה ביציאה ולא עשו לה בכניסה אין ממלאין הימנה בשבת אא"כ עשו לה מחיצה י' טפחים ביציאה ובכניסה ר' יהודה אומר כותל שעל גבה תידון משום מחיצה
THAT WATER WAS DRAWN FROM IT ON THE SABBATH ON THE AUTHORITY OF THE ELDERS.<span class="x" onmousemove="('comment',' Which shows that courtyard walls may serve as partitions for a channel passing under them.');"><sup>29</sup></span> THEY<span class="x" onmousemove="('comment',' The Rabbis who differed from his view.');"><sup>30</sup></span> REPLIED: BECAUSE IT WAS NOT OF THE PRESCRIBED SIZE.<span class="x" onmousemove="('comment',' It was less than ten handbreadths deep or less than four handbreadths wide. Such a channel is regarded as part of the private domain through which it passes and requires no partitions at all. Where partitions, however, are required the courtyard walls cannot serve the purpose');"><sup>31</sup></span>