Kiddushin, Chapter 1, Mishnah 5. This mishnah deals with the ways in which real property is acquired.
The mishnah opens: "Nechasim she'yesh lahem achrayus" - this is the term used for land, for real property. The commentators discuss why it is called by this name, and various opinions are offered.
The three modes of acquisition for land:
"B'kesef" - the buyer gives money to the seller.
"U'vishtar" - the seller writes a document, a deed transferring ownership to the buyer, stating that his field is sold to him.
"U'vachazakah" - the buyer demonstrates ownership through an act performed on the land: fencing it in, digging in it, and the like, acts that show ownership of the property.
The Gemara's clarifications regarding these three modes of acquisition:
Acquisition through money: it works on its own only in a place where the custom is not to write a deed. But in a place where a deed is customarily written, the buyer does not acquire until the deed is written as well.
Acquisition through a deed: it acquires on its own only when the land is being given as a gift. In a sale, however, the acquisition does not take effect until the money is paid as well - that is, even when money is not being used as the mode of acquisition but rather a deed, the deed is not effective until the money has been paid.
There is one exception to this in a sale: one who sells a field because of its poor quality, and is eager to get it out of his possession - here it is enough to hand over the deed, even though he has not yet received the money for it.
"Nechasim she'ein lahem achrayus nikninin im nechasim she'yesh lahem achrayus":
The mishnah now deals with items that are not land - anything not included in the category of real property. These are acquired together with the land, "b'kesef u'vishtar u'vachazakah", through the three modes of acquisition that work for land, even though these modes do not work for movable property on its own. Since the acquisition of the movables is accomplished by attaching them to the acquisition of the land, when the land is acquired through its own mode of acquisition, the movables come along with it through that very same act of acquisition.
"Zokkin" - the law of gilgul shevuah, the extension of an oath:
The final section of the mishnah does not deal with the laws of acquiring objects, but with a distinction between movables and non-movables for a different purpose. The law is that "one does not take an oath concerning land" - oaths are not administered for claims involving real property, but only for claims involving movable property. However, when a person becomes obligated to take an oath concerning items that are not real property, then by force of gilgul shevuah - that once a person is taking an oath, additional matters can be included in it - he can be required to swear concerning the real property as well.
This is the conclusion of the mishnah: "Zokkin nechasim she'ein lahem achrayus es nechasim she'yesh lahem achrayus" - the property that is not real property obligates the property that is real property, so that the one taking the oath must swear concerning the real property together with the movables.
In summary: in this mishnah we learned that "property that has achrayus," meaning real property, is acquired through money, through a deed, and through chazakah, and we noted the Gemara's clarifications regarding each of these modes. We also learned that property that does not have achrayus is acquired along with the land through those same three modes, and that by force of gilgul shevuah the property that does not have achrayus obligates the property that has achrayus, so that an oath is taken concerning it as well.