Siman - Eruvin Daf 90
- Walking on a roof and an אדכסדרא
Rami bar Chama asked a question, but due to his quick mind, he did not formulate it properly. The Gemara clarifies that his question was, שתי אמות בגג ושתי אמות באכסדרה מהו – What is the halachah regarding carrying an object two amos on the roof and then another two amos on the roof of a portico belonging to someone else? Rashi explains that the portico in question is a karmelis because the roof area which has not been enclosed for residential purposes is greater than two beis se’ah. Do we say that since neither roof is חזי לדירה - fit for residence, it is considered one reshus, even though they are owned by different people, or do we say that since carrying from one roof to another roof is forbidden according to the Chochomim, because each roof is independently owned, so too here since the roof and the portico are independently owned? The Gemara leaves the question as a תיקו.
- Rav applies gud asik to the walls surrounding the roof
The Gemara brings a machlokes Rav and Shmuel and reconciles it with an earlier machlokes brought on Daf 89a that seems to contradict their opinions here. In a case of adjoining roofs on the same level according to Rebbe Meir, or on a single roof according to the Chochomim, Rav says, מותר לטלטל בכולו – it is mutar to carry on the entire roof area, and Shmuel says, אין מטלטלין בו אלא בארבע – we may only carry within an area of four amos.
Rav says it is permitted to carry on the entire roof, which seems to contradict his previous ruling that we do not apply the rule of gud asik to the walls that separate the roofs underneath. Since each roof is completely open to the other roof, he forbids carrying on each roof beyond four amos. The Gemara answers that in the previous case, the wall between one roof and the other was not visible to a person standing on the roof, therefore he does not apply gud asik to that wall. Here, the walls surrounding the roof are visible to a person standing on the roof, therefore gud asik applies to that wall and the roof is considered a single reshus. The Gemara continues with resolving the seemingly contradictory rulings of Shmuel.
- Carrying in and on a ship
In the case of a ship whose area exceeds two beis se’ah, Rav says it is permitted to carry throughout the entire ship and Shmuel says that one may only carry within four amos. The Gemara explains that according to Rav who permits carrying throughout the ship, מחיצתא דהא איכא – there are valid walls enclosing the ship and these walls are considered to have been made for the use of dwelling within the ship. According to Shmuel, one may only carry within four amos because, מחיצות להבריח מים עשויות – the walls of the ship are made primarily to keep water out rather than make the ship a suitable place for dwelling.
Rav Gidal said in the name of Rav Chiya bar Yosef that Rav concedes that if the ship were turned upside down on land so that the bottom of its hull is now the roof, he would be restricted to carrying within four amos. The Gemara clarifies that this is referring to a case where the boat was turned upside for tarring. The walls are therefore not for residential use, and the hull is like a karpaf exceeding two beis se’ah. Therefore, it is a karmelis and carrying more than four amos is forbidden.
