Ohalos, Chapter 8, Mishnah 1. This chapter teaches us a fundamental classification. An ohel can be formed out of an enormous variety of materials, but al pi halacha there are only four categories of ohel, and the categories are defined by what the ohel actually accomplishes.
The four categories
The Mishnah lists them:
- "Yesh mevi'in es hatumah vechoitzetzin": some ohalim perform two functions at once. They transmit tumah downward to an adam or to keilim positioned under them, and they equally act as a chatzitzah. Interpose such an ohel, with the tumah on one side and an adam or keilim on the other, and the tumah is halted so that they remain tahor.
- "Mevi'in es hatumah velo choitzetzin": an ohel with the power to convey tumah to an adam and to keilim, but with no power to hold tumah back.
- "Choitzetzin velo mevi'in": the reverse, an ohel that bars tumah from passing but does not carry it.
- "Lo mevi'in velo choitzetzin": an ohel that accomplishes neither the one nor the other.
Examples of each of the four will follow, be'ezras Hashem. Our Mishnah begins with the first group.
"Eilu mevi'in vechoitzetzin"
These are the items that work in both directions. If they are spread above an adam or keilim, and tumah is underneath together with them, the tumah is drawn onto the adam and the keilim even without any contact with the tumah itself. And in the reverse situation they protect: tumah lying beneath them will not rise to what is above them, and tumah resting on top of them will not descend to what is below them. This is the complete ohel, effective from either side.
The large vessels
"Hashidah": a large chest, of the size of an aron. There is another explanation that it was a type of coach in which the sarim, the ministers, would travel.
"Vehateivah": the Bartenura explains that a teivah is a chest smaller than the shidah, of the kind a shulchani, a money changer, keeps in front of him for his coins. Even so, we are still speaking of a substantial box. Recall Maseches Keilim, Perek 24, where the Mishnah presented long lists of items, each one divided into three levels. There we learned "shalosh teivos hein": the teivah whose opening is on its side is temei'ah midras, since one would sit or lie on it; the one whose opening is on top receives only tumeis meis; and "habo'ah bemiddah", the very large one, is "tehorah miklum", entirely outside tumah. Which teivah is our Mishnah discussing? The third one, the large one. Granted it does not reach the dimensions of the shidah mentioned just before it, but it is large enough to remain tahor.
"Vehamigdal": literally a tower, meaning a tall cabinet with shelves, in which the keilim of the house were stored. We have encountered it in earlier mishnayos.
"Kaveres hakash": a big basket woven from straw; sometimes such baskets were woven from willow or from date palm. "Kaveres hakanim": the same sort of large basket, woven from reeds.
"Uvor sefinah alexandris": this too is familiar from Maseches Keilim. These were the great ocean going ships. One might imagine that at sea drinking water is the one thing never lacking, since the whole ocean surrounds you. But salt water cannot be drunk. Travelers therefore had to carry their own drinking water with them, or else hope for rain. So the ship carried an enormous vessel, a kind of cistern, in which the drinking water was stored, and that cistern is the "bor" our Mishnah speaks of.
The two conditions
All of these vessels block tumah only "sheyeish lahem shulayim", provided they have a base, meaning a flat bottom on which they rest in one spot. If a vessel is built so that it can be rolled from place to place, this halacha does not apply to it.
The second requirement is size: "vehein machzikim arba'im se'ah belach, sheheim korayim beyavesh", their capacity must reach forty se'ah of liquid, which in dry measure amounts to two kor. This qualification applies to each of the vessels named above. Forty se'ah of liquid is a familiar figure, since that is the quantity of water required for a kosher mikveh; two kor of dry material, seeds or peiros, works out to something like sixty se'ah. A keli of such a capacity lies entirely beyond kabbalas tumah, and it likewise stands as a barrier before tumah.
Smaller items that spread and block
The Mishnah now turns to items that are not large vessels at all, yet also both convey tumah and hold it back.
"Vehayiri'ah": a woven sheet of cloth or of hide, stretched out as a covering, forming a roof over whatever is beneath it. "Veskortya": a leather apron. "Vektavlya": a leather sheet. "Vesadin": a cloth sheet, an item we have met many times. "Umapetz": a soft mat, woven of pliant reeds. "Umachtzailes": a stiff mat, woven of hard reeds, also familiar from earlier mishnayos.
In all of these the Mishnah requires "she'asuyin ohalim", that they were fashioned into tents. Once that is done, they carry the full din of an ohel and accomplish everything an ohel accomplishes. A meis beneath such a covering, with an adam or keilim there as well, and the tumah spreads to them. Tumah beneath it, with an adam or keilim above, and the covering holds the tumah back; tumah above it, with an adam or keilim below, and again the tumah is blocked.
And what if the material is not set up in the form of a tent? Suppose one simply raises four poles and spreads the sheet across the top, like a chuppah. That does not qualify. There must be a wall as well as a roof, in the manner of a tent.
Here a question presents itself. Several of these items are themselves mekabel tumah. Have we not established that anything which is mekabel tumah cannot serve as a chatzitzah before tumah? The Bartenura answers that the rule applies to something functioning as a keli. An ohel, however, blocks tumah even though it is subject to tumah.
A herd of animals
The catalogue of items that operate in both directions continues. Under an ohel of this sort an adam or a keli contracts tumah, while whatever is positioned above it, or tumah positioned above it, is held off. "Ve'eider beheima temei'ah utehorah": livestock standing together, and it makes no difference whether the animals belong to tamei species or to tahor ones.
Animals? Where is the ohel here? We are not speaking of building something out of the animals. Rather, a herd is standing pressed together, the undersides of their bellies are more than a tefach above the ground, and the gaps between one animal and the next are less than a tefach. Should there be a meis in that space, the tumah spreads, because for all halachic purposes the bellies of the animals form the roof of an ohel. Whatever is beneath becomes tamei, and whatever is above does not, since an ohel blocks tumah.
The Bartenura adds a qualification: this holds only when the herd is standing in place. A herd on the move is not an ohel. The Rambam maintains that even a herd in motion constitutes an ohel.
Nests, and a bird
The enumeration of things that carry tumah downward and also stop it from passing goes on. "Umechoines chayah va'of": the lairs in which chayos, wild animals, live, and the places where birds settle.
From which shoresh does "mechoines" derive? The Bartenura sends us to Az Yashir, to the words "machon leshivtecha pa'alta Hashem". The pasuk in full: "Tevi'eimo vesita'eimo behar nachalascha", Hashem will bring them in and plant them upon the mountain of His nachalah, "machon leshivtecha", the settled site prepared for His dwelling, "pa'alta Hashem", which Hashem's own hand has made, and the reference is to the Beis Hamikdash. A "machon", accordingly, is the place where a creature makes its home.
The Tiferes Yisroel notes where the chiddush lies: no person constructed these; the chayos or the birds made them themselves, and they are nonetheless an ohel. And a point on the translation: birds obviously build nests, but do chayos build nests? The word does not mean a nest in the sense of a bird's nest. Wild animals do fashion places for themselves and dwell in them.
"Veha'of sheshochein": a bird itself, resting so that it forms an ohel over a meis. The Bartenura explains that this applies where the bird is tied to a wall or to a tree. Untied, it is not an ohel, since it will not remain in place. Bear in mind that ofos can be very large creatures.
A mother in the field
"Veha'oseh makom libnah bashibolin": picture a mother out working in the field with her young child alongside her, whether she is watching him or simply had no one else to leave him with. She sees the sun beating down on him, and a mother finds a solution: she bends the standing stalks of grain together and shapes them into a roof over the child, so that he sits in the shade. That shelter is a full fledged ohel.
Broad leaved plants
"Ha'iros vehakison": two plants are being named, and it is their foliage that the Mishnah has in mind, the leaves of the iros and the leaves of the kison. "Veyarkos chamor": another plant altogether, whose name means the greens of a donkey. The Bartenura ties all three together: each is a vegetable variety that puts out "alim rechavin", wide leaves.
The Rambam adds that the leaves of these particular species remain in place the entire year, and that they measure a tefach by a tefach. Leaves that drop off would not count as an ohel, neither to convey tumah nor as a chatzitzah, a point that will become clearer in the next mishnah, be'ezras Hashem Yisborach. There is another reason offered for treating these leaves as an ohel: they are so thick and sturdy that the wind does not stir them. This is the approach of Tosfos in Maseches Sukkah.
Everything here concerns foliage that is still joined to the ground. Once it has been picked, matters divide. Should it have been wet down by any of the seven mashkin, it has become capable of contracting tumah, and it can then no longer function as a barrier. Should no such liquid have reached it, it falls under the heading of tahor foods, a case the Mishnah takes up in a moment. Our subject, then, is leaves still rooted in the earth, thick and wide, a tefach in each direction, whether because they last out the year or because they are solid enough that a wind will not move them.
"Vedla'as yevanis": the word dla'as appears often in mishnayos and is rendered in various ways, some explaining it as a pumpkin or another member of the squash family. In any case, the Greek dla'as also has broad leaves which form a sort of ohel while still attached to the ground.
Ochlin tehorin
"Va'ochalin tehorim": foods in a state of taharah. The Tosfos Yom Tov clarifies the intent: produce becomes vulnerable to tumah only once it has been wet, following its detachment from the ground, by any one of the seven mashkin. The siman for those seven liquids is Yad shachat dam: yud for yayin, wine; daled for devash, honey; shin for shemen, oil; ches for chalav, milk; tes for tal, dew; daled for dam, blood; mem for mayim, water. Absent such contact after detachment, food is simply not susceptible. And while the crop is still growing there is necessarily moisture on it, since nothing grows without water, yet that moisture is of no consequence.
Up to this point the Mishnah's roster has been unanimous. Here a dissenting view is recorded: Rabbi Yochanan ben Nuri "lo hayah modeh", he would not concede the case of "ochalin tehorin". To his mind foodstuffs never form an ohel, not even food that no liquid has touched and which is therefore not presently ra'uy lekabel tumah, for the plain reason that people do not take shelter under their food.
One item he does allow, "chutz min", excepting, "ha'igul shel deveilah". The igul deveilah turns up repeatedly in mishnayos, and many will recognize it from Perek Eilu Metzi'os, quite possibly among the very first mishnayos or the very first Gemara they ever studied. Figs were dried and pressed into round cakes; these cakes were plentiful, and for whatever reason people did in fact use them to make shade. That, holds Rabbi Yochanan ben Nuri, is the single tahor food capable of forming an ohel. The halacha does not rule like him.
Reviewing the Mishnah
This entire Mishnah dealt with only the first of the four categories: the ohel that both draws tumah, so that tumah and an adam or keli together beneath it renders them tamei, and also serves as a mafsik, so that tumah above or below the ohel does not reach whatever is on the other side. The next mishnah will continue with this same first category.
In review: the Mishnah's opening statement is that ohalim fall into four groups, those that convey tumah and also stop it, those that convey it without stopping it, those that stop it without conveying it, and those that do neither. It then opened the roster of the first group with the sizable containers: chests of various dimensions, hampers plaited from straw or from reeds, and the drinking water tank of an Alexandrian ship, on condition that each has a level bottom and is not built to be wheeled about, and on condition that its capacity reaches forty se'ah of liquid, corresponding to two kor of dry produce such as seeds or fruit, some sixty se'ah. Next came the fabrics and hides: a stretched covering sheet, an apron of leather, a leather spread, a cloth sheet, a pliant mat and a rigid one. Shape any of these into a tent, with a covering overhead and a side, and it is a plain ohel that transmits tumah and bars it.
Then a herd bunched together in one place, kosher or non kosher animals alike. Why specify both? The Tiferes Yisroel proposes that we might have supposed a kosher herd too unreliable to count, its owner being more apt to lead it off, and the Mishnah teaches that it counts nonetheless. Then the homes made by chayos and by birds, though no human hand built them. Then a bird stationed over a meis, which the Bartenura conditions on its being tethered, just as he conditions the herd on its remaining stationary. Then the mother in the field beside her child, arching the standing grain over him for shade, which qualifies as a genuine ohel. Then the wide leaved vegetables, with the reminder that an ohel need not be big: a tefach in length, a tefach in width and a tefach in height suffice. And tahor foods, meaning produce which since its detachment has not yet met any of the seven mashkin and is therefore not yet mekabel tumah. Rabbi Yochanan ben Nuri disputes this, holding that food is not put to use as shelter, and he allows a single exception, the igul shel deveilah, a pressed cake of dried figs.