אין מודדין תחום העיר אלא בחבל של פשתן של חמשים אמה לא פחות שהוא נמתח ביותר ולא ארוך יותר מפני שאינו נמתח כראוי:

With What Are the Shabbos Limits Measured; the Measurement of [Different Types of] Places; Who May Perform the Measurement. Containing 11 paragraphs The city's boundary is only measured with a linen rope of fifty cubits, no less, because it will be too stretchable, and no longer because then it will not stretch properly

If there is a river in front of him, he measures fifty cubits until its end, and then goes back behind it by twenty-five cubits so that the span will be a complete fifty cubits until the river.

He should place the rope opposite his heart and stretch it with all his might.

A measurement should only be taken opposite the city, even if there are mountains and valleys in front of it. One should not go from beside it in a straight line and measure there, but rather measure opposite the city. When he reaches a hill, if the incline is so steep that if a plumb line were lowered from the top [of the incline], it would descend in a relatively straight line and would not diverge on an incline at the lower end of the hill for a distance of four cubits, it is not necessary to measure the ascending or descending slope [of the hill] at all. If the hill has a flat area at its top, he does not measure at all. If the plumbline moves away from being opposite him by four cubits and then contracts by ten out of fifty, meaning that in a walk of five cubits of incline, ten handbreadths rise, then he can see if the edge of the rope reaches his lip, but if it cannot be spanned by a rope of fifty cubits, he measures with a rope of four cubits. One person stands at the foot of the mountain and one above it at a distance of four cubits, and the lower one gives the rope opposite his heart and the upper one opposite his feet, and the lower one ascends to where the upper one stands and the upper one ascends four cubits, and they measure as before. If he is more inclined, for every four cubits of incline, ten handbreadths rise, so they give up on him and estimate the distance based on their judgment. If it is only fifty cubits, they estimate how much it is based on their judgment, and if it is more than fifty cubits, they measure with a rope of four cubits.

If he reaches a valley, if the plumbline diverges away from him down four cubits, one should see if it can be spanned in a rope of nine cubits from its spanning point. If not, it is measured in a rope of four cubits, and it should not be deeper than two thousand cubits. However, if it is deeper than two thousand cubits, the descent and ascent of the entire slope are measured. If the plumbline does not move away from him by four cubits, it can be spanned in a rope of nine cubits from its starting point. If not, the slope of the descent and ascent is not measured at all, but only the plain of the bottom, even if it is deeper than two thousand cubits.

If one arrives at a hill (or valley) and the entire portion of the hill or valley that is opposite the town is more than 50 cubits wide and thus it cannot be spanned, for example, [the hill or the valley] is [situated] to the east of the town, and [the person measuring] is not able to span [the hill or valley] along the entire length of that side, if [the person] can span [that distance] by proceeding within the 2000 [cubits of the Shabbos limits] to the north or to the south, he should proceed there and span [the hill or the valley], as long as it is still within the boundary of the city. If, however, [the person] cannot span [the hill or the valley] within 2000 [cubits] on the town’s sides, he should not proceed further [away from the town] to span that area.

One may rely only on a measurement made by an expert who is knowledgeable regarding the measurement of land

[The following laws apply when] the Shabbos limits [of a town] had been established and an expert came and measured [them again], maintaining that [the Shabbos limits] should be increased [in one place] and decreased [in another]: His rulings should be accepted even regarding the limits he increased. Rema: If [the expert] measured and found that the measure in the northeast [corner] is larger than the parallel measure in the southeast [corner], he should extend the line of the Shabbos limits from [the northeast corner] to the [southeast corner] on a diagonal (Rosh and the Tur). And there are those who say, the resolution or decision will be made based on the level or flatness of the location where the argument occurred. (Beis Yosef in the name of Rashi and the Rashba).

If two experts came and measured [a town’s] Shabbos limits, one [arriving at] a larger measure and the other [arriving at] a smaller one, we [accept the ruling of] the one who arrived at the larger measure. [The above applies] provided that [the larger measure] does not exceed [the smaller measure by] more than [the difference between the measuring along a diagonal from the corner of the town [and measuring from the perimeter of the town]. What is implied? It can be said that the larger measure was arrived at [for the following reason]: Perhaps the first [expert] measured the 2000 [cubits] diagonally from one corner of the city, [proceeding outward] along the diagonal, and he did the same [when measuring] from the other corner. Therefore, when a [measuring] rope is extended from the end of the Shabbos limits from one corner to the end of those limits [measured] from the other corner, the distance between this line and the city will be less than 2000 [cubits]. The [second expert, however,] measured properly, [i.e., perpendicularly] from the [border] of the city. We do not presume that the first [expert] erred by more than this amount. {Ed. Note: Therefore, if the second [expert] added a greater distance than this, [his ruling is not heeded}

The Shabbos limits around a city are configured like a square tablet, i.e., 2000 cubits are measured outward along the entire length of the eastern side of the city and the same is done on its northern side. Afterwards, it is viewed as a square tablet [measuring] 2000 [cubits] by 2000 [cubits] to fill up the corners. Thus, the corner of the Shabbos limits of 2000 cubits on a diagonal will be 2800 [cubits distant from the city]. The same pattern should be followed for all the other corners. However, one should not measure 2000 cubits [outward] diagonally from the center of one corner and do the same from the opposite corner, and then extend a [measuring] rope from one to the other. [The rationale is that] were [the person taking the measurements] to do so, he would forfeit 800 [cubits] on the diagonal, and moreover, the Shabbos limits from the [edge of the] city would be 1428 [cubits].

Even a Canaanite bondman or maidservant {who accepted the observance of the mitzvos in which women are obligated} is [considered as] trustworthy when [he or she] says: “The Shabbos limits extend until here.” A minor, by contrast, is not considered as trustworthy [regarding this matter]. Nevertheless, an adult is considered as trustworthy [if] he says, “I remember that when I was a child we would proceed until this point on Shabbos.” His testimony is relied upon.