Now that we have, with God's help, completed our discussion regarding how to define an area as a Reshut Harabim or Karmelit we will discuss how to construct an eruv. We should note that in the latest volume of the Igrot Moshe (published only a few weeks ago) Rabbi Feinstein presents a detailed explanation of why he believes that the Flatbush Eruv is not acceptable. He presents threin an argument rejecting the ruling of the Chazon Ish and Rav Chaim Ozer Grodinski regaurding the construction of an Eruv in Paris.
Tzurat Hapetach or Delatot ("The Doors")
The first question that must be addressed is whether an area as a Reshut Harabim or a Karmelit. If the area is a Karmelit, then encompassing the area with Tzurot Hapetach is sufficient. However, if the area is a Reshut Harabim it must be encompassed by a wall or doors (דלתות) that are locked at night (Shulchan Aruch 463:2 and Mishna Berura 463:8). We will now briefly discuss the issue of how such doors would be installed in a Reshut Harabim.
The Upper West Side Eruv
An area in which דלתותhave been installed is in the Upper West Side of Manhattan. This Eruv has been designed to accommodate authorities who rule that Manhattan is considered a Reshut Harabim. The Eruv consists of a combination of building faces, the Central Park wall, a fence on the Western boundary, and דלתות that can be extended in places where there were gaps of more than ten cubits without any preexisting "halachic walls" or מחיצות. For a discussion of a type of "door" see the essays that appear in volume twenty one of Noam. For a discussion of how often "the doors" have to be closed and other details regarding the laws of "doors" see Netivot Shabbat (a comprehensive work on the laws of Eruvim that was written fairly recently) chapter twenty three.
It should be noted that besides "doors," Tzurot Hapetach have also been installed for the Upper West Side Eruv. The reason for this is that although "walls" such as building faces and fences constitute a "wall" (מחיצה) on both a Torah and Rabbinic level, regarding דלתות there is a major dispute whether they are effective only on a Torah level or even a Rabbinic level. Although the Chatam Sofer (Teshuvot no. 88) and others rule that דלתות are effective even on a Rabbinic level, the Chazon Ish (Orach Chaim 87:1) writes at length to argue that דלתות are not effective on a Rabbinic level unless Tzurot Hapetach are also present. Both Rav Hershel Schachter and Rav Mordechai Willig (two eminent Rashei Yeshiva at Yeshiva University) find Chazon Ish's reasoning persuasive and they rule strictly accordingly.
The rule as to how to construct a Tzurat Hapetach seems simple and straightforward. The Talmud (Eruvin 11b) states that a Tzurat Hapetach consists of two vertical poles and a horizontal pole on top of the vertical poles - קנה מכאן וקנה מכאן וקנה על גביהו. However, the laws regarding Tzurat Hapetach are actually quite complex. It is especially important to know all the laws of Tzurat Hapetach when constructing a community Eruv, so as to facilitate using as many "preexisting structures" as possible.
Must the Vertical Poles Extend All the Way to the Horizontal
The Talmud (Eruvin 11b) records a dispute between Rav Nachman and Rav Sheishet regarding whether the vertical poles must extend all the way up to the horizontal pole. The halacha concurs with the opinion of Rav Nachman that the vertical pole is not required to extend all the way up to the horizontal pole (Shulchan Aruch 362:11). The Shulchan Aruch explains that if the vertical poles are ten handbreadths (Tephachim) - approximately forty inches high and are positioned precisely beneath the horizontal pole, it is a fully acceptable Tzurat Hapetach. The Mishna Berura (263:26) explains that the basis for this rule is that if all the criteria are satisfied we say "גוד אסיק," "stretch up" the vertical pole and view it as if it extends all the way to the horizontal pole.
גוד אסיק - Eyesight or Plumbline
A major debate has emerged amongst halachic authorities in this country regarding how to determine that the horizontal pole is positioned precisely beneath the vertical pole (see Mishna Berura 263:36). Rav Yosef Dov Soloveichick and Rav Moshe Feinstein both are quoted as saying that it is sufficient to estimate by eyesight alone that the vertical pole is placed exactly beneath the horizontal pole. Others, however, argue that a plumbline is necessary. They point out that the Gemara (Eruvin 49b) requires that "halachic walls" (and presumably "tzurot hapetach") be constructed כדעבדי אנשי - the way people construct walls, openings, and doorframes (this idea is particularly emphasized in Rav Shlomo Kluger's responsa on the topic of Eruvin -see his Teshuvot האלף לך שלמה). Accordingly, since builders and carpenters have been using plumblines since time immemorial (plumblines are mentioned in the book of Amos 7:7) some authorities rule that in constructing a Tzurat Hapetach a plumbline must be utilized. The authorities who told this author that a plumbline is required include Rav Yitzchak Liebes (author of Responsa Beit Avi), Rav J. David Bleich, Rav Herschel Shachter, and Rav Mordechai Willig. When I became aware of this controversy which does not (to the best of my knowledge) appear in any classic halachic sources, I began to investigate what the practice was in other countries. I discovered that the same controversy exists in Israel- some communities use a plumbline and others rely on eyesight alone. I even posed the question to Rav Shlomo Zalman Auerbach z"l when I visited him in his home in 1991. Rav Shlomo Zalman told me that while it is best to use a plumbline it is permissible to rely on eyesight alone if it is "impossible" to construct the Eruv otherwise (of course, the definition of "impossible" is debatable).
In addition, I asked older Rabbanim who served as community Rabbis in pre-World-War-Two Europe, how "Tzurot Hapetach" were constructed in Europe. Rav David Lifshitz זצ"ל (a great Rosh Yeshiva at Yeshiva University who served before the war as the Rav of Suwalk in Poland) told this author that a plumbline was used when constructing a "Tzurot Hapetach" in Suwalk. He acknowledged, however, that he was unaware of what the practice was in other towns in Europe regarding this issue. I subsequently asked Rav Ephraim Eoshry (who served as the Rav before and during the war years in Kovno, Lithuania and later authored the responsa ממעמקים) about this issue, and he said unhesitatingly that in Kovno they relied on eyesight alone. Rav Yosef Singer (from the Lower East Side who served as a Rav in pre-war Galicia) also told me that he remembered that Rabbis in Europe relied on eyesight alone and perhaps only in small towns and villages was a plumbline used.
Accordingly, the debate that has emerged in this country in recent years has been a matter of difference of opinion long before American Jewish communities began to construct community Eruvin. In order to avoid the problem of determining that the vertical poles are installed precisely beneath the horizontal wire, many communities today have decided to erect vertical poles (commonly, though incorrectly called Lechis) that reach all the way to the horizontal pole.
Tachuv - Horizontal Wire Penetrates the Vertical Pole
Another major issue is debated regarding the construction of Eruvim is the question of "Tachuv" - when the horizontal wire does not rest upon the vertical pole, but instead is drilled through the vertical pole. This question is particularly pertinent today when many wires on utility poles, especially cable television wires, are drilled through a hole in the utility pole (it is reported that in one community the owner of the cable television franchise was an observant Jew who had the cable wires installed in a manner that would create a Halachically acceptable Eruv).
The Talmudic background to this question is as follows: The Gemara describes that in a Kosher Tzurat Hapetach, the horizontal pole is placed upon the vertical pole. The Talmud also states that if the vertical pole is not under the horizontal one צורת הפתח מן הצד(), it is unacceptable. The Talmud also does not explicitly address the question: What is the Halacha when the horizontal pole passes through a hole drilled in the vertical pole?
Achronim debate whether this is an acceptable Tzurat Hapetach. On the one hand, the Mishna Berura (263:46) cites the Pri Megadim who is uncertain regarding this matter and is inclined to rule strictly. The strict ruling is based on a reading by Rashi (Erunin 11a s.v. Min Hatzad) who appears to say that placing a horizontal pole in "the middle of the vertical pole is equivalent to placing the horizontal pole to the side of the vertical pole." Both the Aruch Hashulchan (3/2:23) and the Chazon Ish (17:9), however, rule leniently. They both argue that as long as the horizontal wire passes through a part of a pole which is higher than the ten Tephachim, we can ignore (Dal Me'hacha) the portion of the vertical pole which is above the horizontal pole. The Chazon Ish reasons as follows: If a horizontal pole were placed on a vertical pole and subsequently a second vertical pole was placed on top of the vertical pole on the place where the horizontal rested on it, isn't it obvious that this is acceptable? Why then, argues the Chazon Ish, should a horizontal wire which passes through a hole drilled in a vertical pole not be deemed Kosher?
This issue has not been resolved and some Eruvim rely on the lenient opinions while others subscribe to the strict opinions. Both Rav Yehuda Amital and Rav Herchel Schachter told this author that the practice in Israel is to be lenient in this issue. This is not surprising in light of the fact that the great Chief Rabbi of Jerusalem, Rav Zvi Pesach Frank z"l rules leniently on this issue (Teshuvot Har Zvi O.C. 2:81:3).
Next week, we take a break from Eruvin and discuss the great importance of signing a Halachically valid prenuptial agreement. The week afterwards, God willing, we will continue our discussion regarding how to construct an Eruv.