Bava Batra

R. Papa said: [A balance used] for heavy pieces of metal. R. Mani b. Patish said: The same [restrictions] that have been said [to apply to balances] with reference to their disqualification [for commercial uses] have also been said [to apply to them] with reference to their [liability to] Levitical defilement.  What does he come to teach us? [Surely] this has [already] been taught [in the following]:  The [length of the] cords  of a shopkeeper's, and of producers' balances [which may be subjected to the laws of Levitical defilement, must be] one handbreadth! [And, since this restriction  has specifically been applied to one kind of balance, are not the other kinds of balance to be implied?]  — [The statement of R. Mani] is required [on account of the sizes of] the beam and the cords, which have not been mentioned [there]. Our Rabbis taught: Weights must not be made either of tin or of lead or of gasitron  or of any other kinds of metal,  but they must be made of stone or of glass. Our Rabbis taught: The strike must not be made of a gourd because it is light,  nor of metal because it is heavy,  but it must be made of olive, nut, sycamore, or box wood. Our Rabbis taught: The strike may not be made thick  on one side and thin on the other.  One may not strike with a single quick movement, for striking in this manner causes loss  to the seller and benefits  the buyer. Nor may one strike very slowly because [this] is disadvantageous  to the buyer and beneficial  for the seller. Concerning all these [sharp practices of traders], R. Johanan b. Zakkai said:  Woe to me if I should speak [of them]; woe to me if I should not speak. Should I speak [of them], knaves might learn [them]; and should I not speak, the knaves might say, 'the scholars are unacquainted with our practices' [and will deceive us still more]. The question was raised: Did he [R. Johanan] speak [of these sharp practices] or not? R. Samuel son of R. Isaac said: He did speak [of them]; and in so doing  [he based his decision] on  the following Scriptural text: For the ways of the Lord are right, and the just do walk in them; but transgressors do stumble therein. Our Rabbis taught:  [It is written], You shall do no unrighteousness in judgments in meteyard, in weight. or in measure.  In meteyard relates to the measuring of ground; one should not measure out for one person in the hot  season and for another in the rainy  season. In weight, [means] that one shall not keep his weights in salt.  In measure, that one shall not cause [liquids] to froth.  And by inference from minor to major, [the following may be deduced]. If the Torah cared [for proper measure in] a mesurah  which is one thirty-sixth of a log. how much more [should one be careful to give proper measure in the case] of a hin.  half a hin, a third of a hin, a quarter of a hin, a log,  half a log, a quarter [of a log], a toman,  half a toman and an 'ukla! Rab Judah said in the name of Rab: A person is forbidden to keep  in his house a measure [which is either] smaller or larger [than the nominal capacity] even if [it is used as a] urine tub. R. Papa said: This applies only in [the case of] a place where [measures] are not [officially] marked,  but where they are [officially] marked [they may be used; for] if [the buyer] sees no mark he does not accept [them] — And even where they are not marked, this has been said only in the case where they are not supervised,  but if they are supervised  it does not matter. But this is not [right]; for [the buyer] may sometimes happen [to call] at twilight  and accidentally accept [the faulty measure]. The same, indeed, has been taught [in the following]: A person must not keep in his house a measure [which is either] smaller or larger [than the nominal capacity], even if [it is used as a] urine tub. But a person may make a se'ah,  a tarkab,  half a tarkab, a kab,  half a kab, a quarter [of a kab], a toman,  half a toman