1)

(a)The Beraisa rules that if a river swept away Reuven's beams, wood and bricks and deposited them in Shimon's field - Shimon may keep them, because the owner must have known about it and been Meya'esh.

(b)We extrapolate from there - that in a regular case of Metzi'ah, where Reuven was not aware of the loss at the time, Shimon would be obligated to return the objects, a Kashya on Rava.

(c)To answer the Kashya - we establish the Beraisa where there is no Si'man, and Shimon may keep the beams, wood and bricks even though Reuven was able to save them at any time; and the equivalent by other Metzi'os would be (not that he was unaware of the loss at the time that it occurred, but) that there is a Si'man (enabling him to claim).

2)

(a)The Seifa of the Beraisa continues - that if Shimon is running after his objects, Shimon is obligated to return them.

(b)If Reuven was able to save his objects easily, then Shimon would indeed be obligated to return them, irrespective of whether Reuven was making efforts to save them or not. We therefore establish the Beraisa - where he is able to save them, but only if he acts quickly and catches them immediately. Consequently, if Reuven is not making any effort to save them, Shimon may keep them.

3)

(a)Another Beraisa discusses a case where Reuven separates Terumah from Shimon's crops without permission. His Ma'aser will take effect - only if Shimon does not consider it an act of theft, otherwise not.

(b)We establish the case where Shimon arrives on the scene and tells Reuven 'K'lach Eitzel Yafos' ('Go to the better ones!') Consequently - if there are indeed better ones, then it is clear that Shimon accepts what Reuven did, and does not consider it as act of theft. If not, he is obviously being sarcastic, and Reuven's Terumah is invalid.

(c)The Terumah will take effect even if there are no better crops to be found - if Shimon takes some crops and add them to Reuven's pile.

4)

(a)As the case stands, where Shimon does not know about the Terumah until after it has been separated, it seems that the Tana holds 'Yi'ush she'Lo mi'Da'as Havi Yi'ush'. Rava therefore establishes the Beraisa according to Abaye - where Reuven appointed Shimon a Shali'ach ...

(b)... and the reason that his Terumah might not be valid is - because most people give a fiftieth as Terumah. Shimon however, assessed Reuven as belonging to the generous group who give a fortieth (and we now need to know whether his assessment was correct or not).

(c)We prove that in any event, this must be the case (and that the Tana cannot be speaking where Reuven Ma'asered Shimon's crops without his prior consent - because we learn from the Pasuk "Gam Atem", that a Shali'ach requires the knowledge of the owner, just like the owner who separates the Ma'aser himself.

5)

(a)When the Aris (sharecropper) of Mari bar Isak found Ameimar, Mar Zutra and Rav Ashi in Mari's orchard, he brought them - some dates and pomegranates.

(b)Ameimar and Rav Ashi ate, Mar Zutra did not.

(c)When Mari bar Isak saw what his Aris had done - he asked him why he didn't offer them some of the better quality fruit that grew in his orchard.

(d)Mar Zutra still refused to eat - because citing Rava, he argued that Chazal only rely on 'K'lach Eitzel Yafos' with regard to separating Terumah (as we learned above), which is a Mitzvah, but not with regard to eating the fruit, where the owner probably said it out of embarrassment (and not with his whole heart).

6)

(a)The Beraisa says that if someone is pleased with the dew ...

1. ... that he finds on his fruit which is drying on the roof - the fruit immediately enters the category of 'be'Chi Yutan' (and is ready to become Tamei, even after the fruit has dried).

2. ... that was previously on the now dry fruit - it does not.

(b)The Seifa poses a Kashya on Rava - inasmuch as the knowledge that the fruit had been wet does not work retroactively (indicating that 'Yi'ush she'Lo mi'Da'as, Lo Havi Yi'ush'.

(c)To answer the Kashya, we cite Rav Papa, who explains the fact that the word "Yutan" (in the Pasuk "ve'Chi Yutan Mayim al Zera" is spelt without a 'Vav' (to read "Yiten") - to teach us that as long as the owner is pleased that his fruit became wet ("Yutan") when it became wet (like "Yiten", where he put the water on it himself ['Yutan Dumya de'Yiten'], then it is Muchshar Lekabel Tum'ah, but not if he was pleased only after it was already dry.

7)

(a)Rebbi Yochanan quoting Rebbi Shimon ben Yehotzadak learns from the Pasuk in Ki Seitzei "ve'Chein Ta'aseh le'Simlaso ... Asher Tovad Mimenu u'Metzasah" - that if at the time when an article gets lost, it is lost, not only to the owner, but to everyone else too (such as one that is swept away by a torrent), it is permitted to the finder, irrespective of whether it had a Si'man or not.

(b)We extrapolate from here - that in the equivalent case where it is not lost to everyone, it is forbidden, irrespective of whether it had a Si'man (where the owner will not be Me'ya'esh when he discovers his loss) or not (where he will), finally disproving Rava.

(c)We rule like Abaye against Rava - in five other cases (known by the acronym of 'Y.A.L K.Ga.M'. - Yi'ush she'Lo mi'Da'as; Eid Zomem Lemafrei'a Hu Nifsal; Lechi ha'Omed me'Eilav; Kidushin she'Lo Nimseru le'Bi'ah; Giluy Da'ata be'Gita; Mumar Ochel Neveilos Le'hach'is'.

(d)Now that Rava has been disproved, Rav Acha Brei de'Rava asked Rav Ashi - for the basis of the Heter to eat dates that have been blown off the palm-tree by the wind.

8)

(a)In reality, Rav Acha bar Rava have could have asked the same question even if Rava had not been disproved - having learned above, that with the exception of figs (that become squashed when they fall off the tree), fruit that falls off the tree is forbidden because the tree is a Si'man (and Rava conceded even before being disproved that when there is a Siman, retroactive Yi'ush does not apply).

(b)Rav Ashi replied - that they are nevertheless permitted, because, based on the owner's knowledge that the wind is bound to blow dates off the tree and that the worms like dates, he is positively Meya'esh at the outset.

(c)Eating dates that have fallen from palm-trees that belong to young orphans (who do not have the power to be Mochel or Mafkir) is prohibited, though we will not forbid eating the dates from any date-palm in any given area, in case the tree from which they fell belong to a young orphan.

(d)Rav Ashi also forbids the dates in the case of 'Karsh'sa - which is a date-palm belonging to a Gadol, but which is surrounded by a fence specially designed to keep the worms out ...

(e)... in which case, the owner is not Meya'esh.

9)

(a)Rabah establishes 'small sheaves in the Reshus ha'Rabim' (which our Mishnah permits the finder to keep) even when they have a Si'man. According to Rava - the Mishnah speaks specifically when they do not have a Si'man.

(b)The basis of their Machlokes is - whether a Siman that stands to be trodden on (and possibly erased) is still considered a Si'man (Rava) or not (Rabah).

(c)Others present the Machlokes - independently (not in connection with our Mishnah).

10)

(a)We extrapolate from 'K'richos bi'Reshus ha'Rabim', that in a Reshus ha'Yachid, the finder would be obligated to return them - which must speak where there is a Si'man (otherwise why would the finder be obligated to return them in the Seifa?), yet he is permitted to keep them in the Reisha, a Kashya on Rava.

(b)Rava replies - that the Tana is speaking, not where the sheaves have a Si'man, but where Makom (the place itself) is a Si'man.

(c)Makom is not a Si'man in the Reisha however - because small sheaves tend to get kicked around from one place to another.

(d)According to Rabah - Makom is not a Si'man.

11)

(a)We just learned that our Mishnah draws a distinction between whether one finds small sheaves in a Reshus ha'Rabim or in a Reshus ha'Yachid. The Beraisa adds that if one finds large sheaves - one is obligated to return them even in the Reshus ha'Rabim.

(b)Despite the fact that a Si'man that is going to be trodden on (Rabah) or that is going to get kicked around (Rava) is not considered a Si'man, the finder may not keep large sheaves that he finds in a Reshus ha'Yachid, according to ...

1. ... Rabah - because people do not tend to tread on large sheaves.

2. ... Rava - because people do not tend to kick around large sheaves from one place to another.