property law governs ownership and possession. real property, sometimes called 'real estate', refers to ownership of land and things attached to it. personal property, refers to everything else; movable objects, such as computers, cars, jewelry or intangible rights, such as stocks and shares. a right "in rem" is a right to a specific piece of property, contrasting to a right "in personam" which allows compensation for a loss, but not a particular thing back. land law forms the basis for most kinds of property law, and is the most complex. it concerns mortgages, rental agreements, licences, covenants, easements and the statutory systems for land registration. regulations on the use of personal property fall under intellectual property, company law, trusts and commercial law. an example of a basic case of most property law is "armory v delamirie" [1722]. a chimney sweep's boy found a jewel encrusted with precious stones. he took it to a goldsmith to have it valued. the goldsmith's apprentice looked at it, sneakily removed the stones, told the boy it was worth three halfpence and that he would buy it. the boy said he would prefer the jewel back, so the apprentice gave it to him, but without the stones. the boy sued the goldsmith for his apprentice's attempt to cheat him. lord chief justice pratt ruled that even though the boy could not be said to own the jewel, he should be considered the rightful keeper ("finders keepers") until the original owner is found. in fact the apprentice and the boy both had a right of "possession" in the jewel (a technical concept, meaning evidence that something "could" belong to someone), but the boy's possessory interest was considered better, because it could be shown to be first in time. possession may be nine tenths of the law, but not all.