1)

(a)Rav says that someone who learns something from a Magush is Chayav Misah.

(b)According to Rav, a Magush is - a heretic who also draws others to idolatry.

(c)A Magush might also be a sorcerer. We learn from the Pasuk "Lo Silmad La'asos" - that although it is forbidden to learn sorcery to practice it, it is permitted to learn it in order to deal with it in Beis-Din, should the need arise.

(d)Now Rav just said that someone who learns from a Magush is Chayav Misah, and if he were to hold that a Magush is a sorcerer, then how could the Torah permit the Chachamim to do something for which one is Chayav Misah, whatever the motive?

2)

(a)The Navi Yeshayah writes "ve'Es Po'al Yadav Lo Yabitu u'Ma'aseh Yadav Lo Ra'u", says Rebbi Yshoshua ben Levi - about somebody who has the knowledge to work out the Tekufos (of the sun) and the Mazalos, to be able to foretell, for example, whether the year will be rainy or sunny.

(b)We learn from the Pasuk "u'Shemartem ve'Asisem ... le'Einei ha'Amim" - that it is a Mitzvah to work out the Tekufos and the Mazalos.

(c)"le'Einei ha'Amim" indicates - that this Chochmah shows up the Chochmah of Yisrael in the eyes of the nations of the world, when their predictions come true. This is a Kidush Hash-m, and seems to be why Chazal refer to it as a Mitzvah.

(d)Rav Zutra bar Tuvah Amar Rav says - that one may not speak to someone who fails to put this knowledge into practice.

3)

(a)According to Rebbi Yehudah in a Beraisa, catching a Chilazon fish and squeezing it for its blood, involves the Melachos of Tzeidah and Dishah (trapping and threshing [i.e. extracting its blood]). The Tana Kama exempts him from Dishah - because it Dishah is confined to things that grow from the ground, and is therefore not applicable to fish.

(b)According to Abaye, the Mishnah does not include the Melachah of Netilas Neshamah (killing the fish), because we are speaking here about a fish that is already dead. Rava establishes the Beraisa even by a fish that is still alive when he begins to squeeze it, and the reason that he is not Chayav for Netilas Neshamah is because in Rava's opinion, someone who squeezes a fish for its blood is considered 'Mis'asek' (unintentional) - since he does not really intend the fish to die.

(c)Despite Abaye and Rava's having said that even Rebbi Shimon (who permits a 'Davar she'Ein Miskaven') agrees that one is Chayav when it is a case of 'P'sik Reisha' (inevitable) - here Rava holds he is Patur, because it Rava considers 'Mis'asek' a 'P'sik Reisha de'lo Nicha Lei' (a 'P'sik Reisha' that he does not want), for which he is not Chayav (and which is even permitted Lechatchilah, according the Aruch [see Tosfos DH 'Mis'asek]).

4)

(a)According to Rav, someone who Shechts is Chayav for taking a life - and for Tzovei'a (dyeing).

(b)The advantage of a blood-red neck is - that it attracts customers.

5)

(a)Molei'ach and Me'abed are one and the same, so one of them is dropped from the Mishnah. The Melachah that replaces it - is Sirtut' (marking the skin for cutting).

(b)According to Rabah bar Rav Huna, one is Chayav for salting meat. Rav Ashi qualifies this - by confining it exclusively to someone who salts it to take with him on a long journey, but not to someone who salts it at home (because, except when traveling, one does not usually salt meat suffiently to render it hard like a piece of wood ), and salting that is solely for taste is not called Molei'ach.

(c)According to Rava - Melichah does apply to food - though this does not necessarily mean that it is permitted (see Tosfos DH 'Ein').

(d)'ha'Shaf Bein ha'Amudim' means - someone who smoothens the ground between the pillars of the porch.

6)

(a)'Megarer Roshei Kelunsa'os' means - sharpening the tips of poles, which involves the Melachah of Mechatech.

(b)If, on Shabbos, someone ...

1. ... rubbed a dressing (consisting of fat) on a wound , he would be Chayav for Memare'ach.

2. ... smoothened a stone after it was mined from the quarry - he would be Chayav because of Makeh ba'Patis.

3. carved a picture on a vessel (which intended for that purpose), to have a picture on it, blew a glass vessel or removed excess strands from curtains or from a garment - he would be Chayav because of Makeh ba'Patish.

(c)However, he would only be Chayav for the removal of the strands in the latter case, if he was fussy not to use it or to wear it, the way it was.

7)

(a)One is Chayav ...

1. ... only if one writes two letters (of the alphabet) - but not for one, even if takes up the space of two.

2. ... for erasing one large letter, leaving sufficient space to write two.

(b)The difference between writing and erasing in this regard is - due to the fact that writing in is itself, a Melachah (with a minimum Shiur of two letters); whereas erasing, which is a Kilkul, is only Chayav inasmuch as it prepares the space to write - and writing, as we have already pointed out, has a Shiur of two letters.

8)

(a)The Chidush of 'Eilu Avos Melachos' is - that however many Melachos one performs, the maximum number of Chata'os that he needs to bring will be thirty-nine (since one is never Chayav for performing a Toldah once one is Chayav for its Av). This comes to preclude the opinion of Rebbi Eliezer, who holds that one is Chayav for performing a Toldah even if he performed it together with its Av.

(b)Rebbi Yehudah inserts the Melachos of Shovet - arranging the threads of the warp onto the reel of the spinning-loom, and Medakdek - striking the threads of the woof as one stretches them (to prevent them from becoming too taut), in the list of Avos Melachos.

(c)The Rabbanan do not include these among the Avos Melachos, because, in their opinion, Meisach incorporates Shovet, and Oreg incorporates Medakdek.

9)

(a)The Mishnah states a K'lal: 'Kol ha'Kasher Lehatzni'a ... '. According to Rav Papa, this comes to exclude Dam Nidah; and according to Mar Ukva, the wood of an Asheirah.

(b)Mar Ukva holds that Dam Nidah also has a Shiur, because one tends to put it away for one's cat (in those days, even Israelis kept cats!); whereas Rav Papa maintains that no-one would feed Dam Nidah to a cat, because it would cause the cat to become weak.

(c)The author of our Mishnah cannot be Rebbi Shimon, says Rebbi Yossi b'Rebbi Chanina - because according to the K'lal, once a poor man preserves an article that is fit for use, then even a rich man will be Chayav for carrying it out, whereas Rebbi Shimon holds that it is only the person who preserves the article who is Chayav for carrying it out, but not a person who would throw it away.

(d)According to the Tana of our Mishnah, if a person puts away less than the Shiur given in our Mishnah (e.g. less than a ki'G'rogores of food) of something which is not fit to preserve, he is Chayav if he carries it out on Shabbos, but not anybody else. According to Rebbi Rebbi Shimon ben Elazar, says Rebbi Elazar - anyone who carries it out will be Chayav (in the same way as an article which is fit to preserve).