Siman 399

One does not measure the city boundary except with a flax rope of fifty amot. Not less—because it stretches excessively, and not longer—because it is heavy and does not stretch properly. And for what reason do we not measure with iron chains, given that there is nothing better for measurement than iron? Because Zechariah the prophet said: "and in his hand was a measuring rope," (Gemara 58a) implying that measurement must be with a rope, and flax is better for measurement than all other ropes. (ibid.) And in Ezekiel (40) it is written: "and a cord of flax was in his hand." (Yerushalmi) And the reason for fifty is that it is written: "and the width fifty by fifty"—the Torah said: measure with a rope of fifty amot. (Gemara)

If there is a river before him at the end of seventy-five amot, there is a dispute in the Yerushalmi (Chapter 5, Halacha 3). One says that he measures fifty amot, and the twenty-five he shall measure with a rope of four amot; and one says that after he measures the fifty—he goes back twenty-five amot, and measures with the rope until the river. And since in our Gemara a rope of four amot was not mentioned regarding this, we therefore hold that he goes back. (Tur and Beit Yosef). And our teacher, the Beit Yosef, wrote that this deals with a case where the river is wider than twenty-five amot, for if it were only twenty-five or less—could he not measure with the rope of fifty amot, and it would reach until the other side of the river? (Magen Avraham, subsection 1). From this it is clear that the river is included in the calculation of the techum. And in the Yerushalmi there it says, that up to fifty amot we view it as if it were full of earth and pebbles, meaning it is measured like smooth ground; and more than fifty amot—you view it as if it sinks and rises, sinks and descends, and it appears that this is similar to "piercing through mountains" which will be explained. And I wonder that the Tur and the Shulchan Aruch did not mention at all the manner of measuring a river when it is within the techum. And know, that this which we said "that it holds such and such"—it is only based on an estimate, for if we knew clearly how much it holds—behold, there would be no need to measure. (Perisha)

The measurement is performed by two people, this one holding one end of the rope, and that one holding the second end. And the sages ordained that they should hold it opposite the heart, for if a place were not fixed for them, and this one were to hold it opposite his heart and that one opposite his feet—the rope would be shortened and the techum would be diminished. Therefore, they established a fixed place for the holding of the rope, which is opposite the heart, and they shall stretch the rope with all their strength, for if not so—it will not be stretched properly, and the techum will be shortened.

One should only measure opposite the city; even if there are mountains and valleys opposite it—one should not go to the sides of the city to a place where the ground is level and measure there, and then return to the area opposite the city according to the measurement he measured there in order to swallow the mountains and valleys, but rather he must measure exactly opposite the city. And if he encounters a mountain, if the mountain is so steep and is not fit for walking, to the extent that if they were to lower a builder's plumb line from the top of the mountain to the foot of the mountain the slope would not be further than four amot from the top in its span—then there is no need to measure the incline of the mountain at all, neither below nor above, but rather if there is a level place at its top—he measures it there, and if not—there is no need to measure it at all, since it is not fit for walking at all. However, if the incline is not so steep, such as if the slope is further than four amot from the top, and it also gathers ten tefachim within five amot, meaning that in a walk of five amot on the incline it then rises ten tefachim in height and not before, then we see if from its edge to its edge there are only fifty amot—he swallows it with the measuring rope which is fifty amot, and that is by erecting a tall pole from its edge on this side and a tall pole opposite it on its other edge and stretching the rope from this one to that one, and he sees the measurement exactly.

And if according to the sight of the eye it is not possible to swallow it with a rope of fifty cubits—in this they said "one pierces through the mountains," meaning that he measures with a rope of four cubits, and one stands at the foot of the mountain below and one is distant from him four cubits above, and the lower one places the rope opposite his heart and the upper one opposite his feet, and afterwards the lower one ascends to the place where the upper one stood and the upper one ascends and distances himself from him four cubits as before, and they measure as at first, this one opposite his feet and this one opposite his heart, and so they shall do until the completion of the mountain. However, if it is more sloped, and that is where the cord distances four cubits from the foot to the head, but it does not gather ten out of five but rather out of four, that in an ascent of four cubits the height distances ten handbreadths—then they were lenient regarding it and did not trouble him to swallow it with a rope of fifty cubits by means of erecting wood, but rather if according to the estimation there is not more than fifty cubits in it—he shall estimate it with a fine estimation of the mind how much is in it and so he shall reckon. But if according to the estimation there is more than fifty cubits—against his will he must perform the piercing with a rope of four cubits as I have written, for since the cord distances four cubits—it is fit for walking.

If he reached a valley, if the plumb line recedes from the bottom to the top four cubits, and if so it is fit for walking, then we see: if he can swallow it with a rope of fifty cubits—he swallows it, and if not—against his will he measures it with a rope of four cubits. And regarding the swallowing of a valley, there is no distinction between whether it gathers ten out of five or out of four, because even if it gathers ten out of four—it specifically requires measurement; thus it is explained according to the commentary of Rashi (58a) and to the Rambam in chapter 28. The Rashba, of blessed memory, holds that even in a valley there is this distinction, and the Maggid Mishneh already wondered at him there.

However, regarding a valley there is another matter, namely that this is all when the valley is not deeper than two thousand amot. But if it is deeper than the measure of the techum Shabbat - there is no permission for swallowing, rather he measures the descent and the ascent as smooth ground, and the entire slope requires measurement. And why did they not say so regarding a mountain? It seems to me because regarding a mountain there is a further leniency at such a height, for there is no techum above ten tefachim, which is not the case in a valley. And if the plumb line does not distance itself four amot, then if he can swallow it with a rope of fifty amot - he swallows it, and if not - he does not measure the slope of the descent and the ascent at all, but rather the level ground below, even if it is deeper than two thousand, and see what I wrote in siman 404, section 5.

And know that according to the Rambam, chapter 28, law 11, even when the plumb line descends opposite it, where we said that he only measures the level ground below when he cannot swallow it, and even if it is deeper than two thousand—nevertheless, it may not be deeper than four thousand amot; see there. The Tur and the Shulchan Aruch did not bring this. However, regarding the essence of the matter, I do not understand that which we say, whether regarding a mountain or a valley, that when the plumb line distances the bottom from the top by four amot, it is called "fit for walking." And it is a great wonder: in a valley when its depth is two thousand amot, how is it possible to call a deviation of four amot over a vast span of two thousand amot "fit for walking"? And likewise regarding a mountain when it is very high. And in truth, in the Rambam there is no measure of four amot at all when the plumb line does not descend opposite it; see there. And that which is found in the Gemara there: "And when the plumb line does not descend opposite it, until how much? Until four," he does not interpret it as "until four amot" according to the explanation of Rashi and Tosafot, but rather regarding the depth of the valley, that it may be up to four thousand amot, and from this he derived his ruling. But when it does not descend opposite it, he would interpret that the slope must be fit for walking, and whenever it is deeper or higher, it requires a greater distancing of the bottom side from the top side. (And according to Rashi and Tosafot, and especially according to the Rashbam there in Tosafot starting with "And when," it requires great study.)

The sages facilitated a further leniency regarding the matter of swallowing fifty amot, which was explained concerning a mountain and a valley: that if he cannot swallow it—meaning it is much wider than fifty amot—he must measure with a rope of four amot. Our sages, of blessed memory, said that even if he cannot swallow it on the side facing the city, but further away he can swallow it—for example, if the mountains and valleys are on the eastern side, and facing the city they cannot swallow but further from the city and outward, facing north and south, it is possible to swallow—he should swallow there. He measures and proceeds there from its edge onward, until he is opposite the place where the width of the valley ends facing the city, and he returns to his measurement facing the city and completes the measurement of the techumin. (Rashi on the Mishnah 57b). And specifically within the two thousand amot that are on the side of the city to the north and south. But if he cannot swallow it within these two thousand amot, he should not distance himself further on the side of the city in order to swallow it, so that they do not say the measurement of the techumin reaches until here.

One may only rely upon the measurement of an expert person, for he knows how to measure the land, as there is wisdom and knowledge in this regarding how to measure. The measurement must be in a straight line, and one should not look at how the path goes, for paths for the most part go and curve here and there. And if we had established techumei Shabbat, that until here is the techum Shabbat, and one expert came and changed it, and here he increased and here he decreased—we listen to him even in the place where he increased, and certainly in the place where he decreased. And we say that over the course of time this side and that side changed from mountain to plain and from plain to mountain or to a valley and the like, and we do not say that the predecessors erred. And it appears to me that the reason an individual is believed to remove it from the previous presumption is because it is possible to clarify, and any matter that is likely to be revealed—people do not lie about it.

It is a clear matter that the equalization of the sides is only regarding the houses of the city and the outskirts, and not regarding the techumin. That is to say, it has already been explained in the previous siman that if one house protrudes further than the houses of the city, we extend the measure also to the other side to equalize it; and similarly with houses of the outskirt of seventy cubits and a fraction, we extend the measure also on the other side so that it shall be an outskirt for the city, and the techum is measured from there and onward. But this is not so regarding techumin; for example, if in the northeastern corner there were no mountains or valleys and the techum was long, and in the southeastern corner there were mountains and valleys and through this the techum was shortened—we do not equalize this side with the side of the northeastern corner. Rather, in the northeastern corner we follow its measurement, and in the southeastern corner we follow its measurement, and so too anything similar to this. (And I have seen those who erred in this.)

This is what the Tur wrote: "If he measured and found his measurement in the northeast corner exceeded its counterpart, the southeast corner, he stretches the cord of the techum mark from this one to that one diagonally." Thus far his words. This is the opinion of the Rosh, but Rashi, of blessed memory, explained that we extend the measurement from the short place corresponding to the long place. Our teacher, the Rema, brought both opinions in section 8, see there. And it is not because Rashi maintains that even regarding a techum we extend the measurement corresponding to the long side, for he explicitly explained the reason in the Mishnah as being that we attribute it to an error, that perhaps he did not stretch the rope sufficiently in this corner. But the Rosh maintains that we do not attribute it to an error; rather, we attribute it to the fact that on the short side there were mountains and valleys. And if it is difficult, for it is possible to clarify, one can say that this matter is difficult to clarify, as it requires an expert for this. And if an expert truly comes and clarifies, we act according to his words.

If two experts came and measured the techum, one increased and one decreased, and they went on their way and did not clarify the matters with one another to know which measurement was according to the law—we follow the lenient view, and we listen to the one who increases, for techumin is rabbinic. And since they measured on one side and at one corner—we say that the one who shortened erred in the law, and we say that the one who decreased measured from the corner of the city itself, and measured on the diagonal and not on the side, and therefore his measurement was decreased, for according to the measurement of the side it would be less than two thousand, and the one who increased measured from the side according to the law. But in more than this—we do not presume that the first one erred. Therefore, if the difference between them is like the measurement of the diagonal of the city or less than this—we attribute it to an error, but more than this—we do not attribute it to an error, and this measurement is slightly more than five hundred and eighty amot. (Magen Avraham, subsection 6)

One makes the techumin like a square tablet, that is, one measures across the entire length to the east two thousand amot outward, and similarly to the north, and afterward one views it as if there were a square tablet at the corner to fill it, and it turns out that the techum at the corner is two thousand and its diagonal, which is two thousand and eight hundred amot. But one should not measure from the actual corner two thousand diagonally, and similarly at the opposite corner, and stretch the line from this one to that one, for if so, one loses the eight hundred amot at the corner. Furthermore, the techum opposite the city would only be one thousand four hundred and twelve amot, and similarly on every side of the sides of the city. And this that it is like a square tablet—this is in a city that is square, two thousand by two thousand. But in a city whose length is greater than its width, if it is only with equal angles—there is no squaring in the techumin, as is understood, and even in a square city the techumin are not square except on smooth ground where there are no mountains and valleys, for if on this side there are mountains and valleys, whereby the techum is shortened, and on the other side there are none—behold it will not be square, and even on the other side one does not extend the measurement from corner to corner if in one there are mountains and valleys and in the second there are none, as I wrote in section 11.

And know, that the approach of our teacher Tam in Tosafot (51a, s.v. "Ke-zeh") and the Rosh, is that the measure of the techum Shabbat is two thousand with their diagonal, which is two thousand eight hundred amot, and consequently, by means of an eruv it is five thousand six hundred amot, and there are those who rely on this, and it requires further study.

Even a male slave, even a female slave, are trusted to say, "Until here is the techum Shabbat." However, a minor is not trusted, for a minor is only trusted regarding a matter that is within his power. (Magen Avraham, subsection 7) But an adult is trusted to say, "I remember that until here we used to come on Shabbat when I was a minor," and we rely on his testimony. The Mishnah (58b) explained the reason that these are trusted is because the sages did not wish to be stringent regarding the essence of the testimony of techumin.