brought to you by Kollel Iyun Hadaf of Yerushalayim
& Revach l'Neshamah - http://www.revach.net
1. Rava: The Amos of Sukah and Mavoy are slightly smaller than the Amos of Kil'ayim.
2. Rav: The laws of Shi'urin (amounts) were given to Moshe Rabeinu at Har Sinai. They are neither written explicitly nor derived from a verse.
3. Rav: The laws of Chatzitzin (intervening substances that disqualify an immersion in a Mikvah) were also given to Moshe Rabeinu at Har Sinai.
4. Rav: The laws of Mechitzin (partitions) were also given to Moshe Rabeinu at Har Sinai.
5. There is a dispute about how much of the ground of the entranceway must be raised in order to decrease the distance from the ground to the Korah.
A BIT MORE
1. Rava maintains that all Amos are comprised of 6 Tefachim. However, the Tefachim of Sukah and Mavoy (Eruvin) are slightly smaller than the Amos of Kil'ayim. While Abaye (Daf 3, #5) admits that he follows only the opinion of Raban Shimon ben Gamliel and not the Rabanan, Rava agrees with both of them.
2. The Gemara explains that although there is an allusion to Shi'urim in the verse, "A land of wheat, barley, etc.," which teaches that the Shi'ur of some laws are based on a wheat-related amount and some on a barley-related amount, etc., this verse is only an Asmachta. These amounts are in fact Halachos l'Moshe mi'Sinai.
3. The Gemara concludes that while many laws of Chatitzin are derived from the Torah, the laws regarding the size of a stain on one's body and whether one cares that it is there or does not care about it (Rubo u'Makpid) are a Halachah l'Moshe mi'Sinai.
4. This refers to the law that a Halachic wall is 10 Tefachim high, and to the laws of Gud Asik, Lavud, and Dofen Akumah.
5. The Mishnah (2a) states that if a Korah is more than 20 Amos above the ground, it must be lowered. One method of doing so is to raise the floor of the entranceway. Rav Yosef says that the width of the area that is raised must be merely one Tefach underneath the Korah. Abaye says that the raised area must be an area of four Tefachim or more.
Next Daf Index to Revach for Maseches Eruvin