Shevuos, Chapter 6, Mishnah 6. This mishnah continues the rule we mentioned earlier - that oaths are not administered concerning land - and comes to clarify what qualifies as land.
The dispute between Rabbi Meir and the Sages regarding something attached to the ground:
Rabbi Meir holds that there are things attached to the ground which nevertheless do not have the status of land, and therefore one can become liable to take an oath concerning them. The Sages disagree with him and hold that their status is that of land in every respect.
What is the case? A person makes a claim against his fellow, a watchman or a custodian, and says to him: "Eser gefanim te'unos masarti lach" - I handed over to you ten laden vines - ten vines full of grapes that are ready to be picked - and the other replies: you only handed me five.
According to Rabbi Meir: This is an admission to part of the claim, and therefore he is liable to take an oath. Even though the vines are attached to the ground, since the fruit is ready to be picked it does not have the status of land.
According to the Sages: Whatever is attached to the ground is like land itself, and therefore he is not liable and does not take an oath.
The law regarding things that can be measured:
The mishnah teaches an additional law: a person takes an oath concerning an object only if its quantity can be determined - by measure, by weight or by number.
A claim that cannot be measured: The claimant says that he handed his fellow a house full of items or a full purse, and the defendant replies: I do not know, this is what you gave me, take what is inside it. In this case he is exempt, since his answer does not specify any particular quantity.
A claim that can be measured: The claimant says that he handed his fellow produce up to a certain mark in the house - such as a protrusion in the wall - and the defendant replies that it was only up to the window, which is a lower mark. Here he is liable, since both the claim and the reply deal with something that can be measured.
The rule that emerges from here: when the claim and the response to the claim revolve around things that can be measured, the obligation to take an oath applies; and when they cannot be measured, there is no obligation.
In summary: In this mishnah we learned the dispute between Rabbi Meir and the Sages regarding something attached to the ground - whether vines laden with fruit that is ready to be picked are considered land with respect to oaths - and we learned that oaths are administered only concerning things whose quantity can be determined by measure, by weight or by number.