Question: How is the barrel positioned?

If the opening faces out (away from the Tum'ah), the barrel itself blocks Tum'ah!

Earthenware Kelim receive Tum'ah only from their interiors!

Answer #1: Rather, the opening faces the Tum'ah.

Answer #2: We can even say that it faces out. The case is, the barrel is made of metal.

Question (Beraisa): The following block Tum'ah: grass that was detached and placed in a window, or grew there by itself; rags smaller than three fingers by three fingers; a dangling limb or flesh of an animal; a bird that rested there; a Nochri who sat there, a (i.e. stillborn) baby born in the eighth month; salt; earthenware Kelim; and a Sefer Torah;

The following do not block Tum'ah: snow, hail, ice, frost, and water.

Summation of question: Grass is fit for an animal, and it blocks Tum'ah!

Answer: It discusses poisonous grass.

Question: The grass blocks, even if it grew by itself. It is destined to be cut, since it damages the wall!

Answer #1 (Rabah): The Beraisa discusses the wall of a ruin (the grass is not destined to be cut).

Answer #2 (Rav Papa): It can even be a wall of an inhabited building. The grass is three Tefachim away (and does not harm the wall), but the top bends into the window.

Question: Why do rags block? They are fitting to patch torn clothing!

Answer: The material is too thick to be used for a patch.

Question: They are fitting for a bloodletter (to clean the wound)!

Answer: They are of sackcloth, which would scratch the skin.

Objection: If so, why did the Beraisa say 'they are not three fingers by three fingers'? Sackcloth is not Tamei unless it is four Tefachim by four Tefachim!

Answer: It is not really sackcloth, just it is scratchy like sackcloth.

Question: Why does a dangling limb or flesh of an animal block Tum'ah? The animal may go away!

Answer: The case is, it is tied down.

Question: Someone may come and slaughter it!

Answer: It is a non-Kosher animal.

Question: The owner might sell it to a Nochri!

Answer: It is a weak animal.

Question: He may cut it up to feed it to dogs!

Answer: That would cause needless pain to a living animal. He would not do this.

Question: Why does a bird that rested there block Tum'ah? It may fly away!

Answer: The case is, it is tied down.

Question: Someone may come and slaughter it!

Answer: It is a non-Kosher bird.

Question: The owner might sell it to a Nochri!

Answer: It is a Kalanisa (a very lean bird).

Question: He may give it to a child to play with!

Answer: He would not, for it scratches.

Objection: A Kalanisa does not scratch!

Answer: It is a different species, but it is as lean as a Kalanisa.

Question: Why does a Nochri who rested there block Tum'ah? He will walk away!

Answer: He is tied down.

Question: A friend will untie him!

Answer #1: He is a leper.

Objection: Another leper will untie him!

Answer #2: Rather, he is a prisoner of the king.

Question: Why does a baby born in the eighth month block Tum'ah? His mother will take him!

Answer: The baby blocks Tum'ah on Shabbos;

(Beraisa): An eighth-month baby is (Muktzeh) like a stone. One may not move him on Shabbos. However, his mother may bend over to let him nurse (without moving him), due to the danger (to him, and to her if she is too full of milk).

Question: Why does salt block Tum'ah? It is fitting to use!

Answer: It is bitter salt.

Question: It is fitting for tanning!

Answer: There are thorns in it.

Question: If so, it harms the wall. He will remove it!

Answer: It is resting on earthenware (and does not harm the wall).

Question: The earthenware itself should block Tum'ah!

Answer: It is too small to block the Tum'ah.

(Mishnah): One is liable for carrying earthenware in a Reshus ha'Rabim on Shabbos if it is big enough to put between bars in a window. (Rashi - anything smaller than this has no importance, it does not block Tum'ah; Tosfos - since it has no use, he will not take it, so the salt blocks the Tum'ah).

Question: Why does an earthenware Keli block Tum'ah? One can use it

Answer: It is dirty.

Question: It is fitting for a bloodletter!

Answer: It has a hole in it.

Question: Why does a Sefer Torah block Tum'ah? One can read from it!

Answer: The case is, it is worn out.

Question: It must be buried!

Answer: Its 'burial' will be leaving in the window permanently.

(Rav): We may make a divider from anything except salt (lest it scatter) and fat (lest it melt).

(Shmuel): Even salt may be used.

Resolution #1 (Rav Papa): They don't argue. Sedom salt may be used, for it is hard and does not scatter. (Regular) salt may not be used.

Resolution #2: Both can discuss (regular) salt, according to Rabah;

(Rabah): One may place the Korah (a beam to permit carrying in an alleyway) on two piles of salt (the weight stops the salt from scattering).

Rav discusses when there is no beam, and Shmuel discusses when there is a beam.

(Mishnah): A millstone's lower stone must be distanced three Tefachim. The upper stone will be four Tefachim away.

Question: What is the reason?

Answer #1: It makes the ground shake.

Objection (Beraisa): The lower stone of a Chamor millstone (Rashi - it is driven by a donkey; Tosfos - one spins it using his feet, not his hands, or it rests on an edifice, and not on the ground) must be distanced three Tefachim. The upper stone must be distanced four Tefachim.

A Chamor millstone does not make the ground shake!

Answer #2: Rather, it is due to the noise.

(Mishnah): The bottom of a Tanur (standard oven) must be distanced three Tefachim. The top will be four Tefachim away.

Inference (Abaye): The bottom of a Tanur should extend a Tefach past the top (in each direction).

This is relevant to commerce (if one sold a Tanur unlike this, it is a mistaken sale.)

(Mishnah): One may not set up a Tanur in his house unless there are four Amos above it. One may not set up a Tanur in an upper story unless there are three Tefachim of plaster below it;

For a Kirah (a rectangular oven, which does not get as hot as a Tanur), one Tefach suffices.

If the oven caused damage, he must pay for it;

R. Shimon says, if he kept the proper distance, he is exempt.

(Gemara) Contradiction (Beraisa): A Tanur must have four Tefachim of plaster underneath. A Kirah must have three Tefachim.

Answer (Abaye): The Beraisa discusses baker's ovens. A baker's Kirah is as hot as a standard Tanur.

(Mishnah): One may not open a store...

(Beraisa): If the pen preceded the storehouse, it is permitted.

Questions (Abaye): If someone cleaned his roof (in order to store food there), but did not yet put food there, is this already considered a storehouse?

If he opened new windows in his Aliyah (in order to store food there), what is the law? If he built an Aliyah (to be a storehouse), what is the law?

These questions are not resolved.

Question (Rav Huna brei d'Rav Yehoshua): If he put in dates and pomegranates, is this considered a storehouse (or only if he puts in grain, wine or oil)?

This question is not resolved.

(Mishnah): In truth, they permitted regarding wine...

(Beraisa): They permitted (a baker's or dyer's store) under wine, because the smoke improves the wine, but not a pen, for the stench spoils the wine.

(Rav Yosef): Even smoke of a candle harms wine of Bavel.

(Rav Sheshes): (The heat and stench of) fodder harms wine just like a pen.

(Mishnah): If one set up a store in a Chatzer, others can stop him because the noise disturbs their sleep;

Rather, he may make Kelim in the Chatzer and sell them in the market.

If their sleep is disturbed by the noise of his hammer, millstone or children (coming to the store) they cannot complain.

Question: What is the difference between the clauses?

Answer #1 (Abaye): The Seifa teaches that people of another Chatzer cannot complain about the noise.

Objection (Rava): If so, it should say so explicitly!

Answer #2 (Rava): The Seifa discusses one who teaches Torah to children, after the enactment of Yehoshua ben Gamla.