In fact the “‘s” clitic is from the Anglo-Saxon genitive case ending “-es, -is, -ys”, as in Godes “of God” or mannys “of man”. When this was mutated into Middle English, the vowel was dropped, leaving “‘s”. Writers as early as John Donne made the mistake of assuming that it meant “his” and not the old genitive ending, Donne using “Methusalem his page” in place of “Methusalem’s page” in one poem.

Consider two trivia that cement the point: one Alchemist has pointed out, that “Jane his car” makes no sense; and the other that “hises”, contracted to “his’s”, was tried and ultimately failed as the Middle English absolute masculine singular possessive.

Thus, when we say “Fred’s car” we really are contracting “Fred, his car”

Of course, it gets all confusing when we talk about James or Jesus or something else ending in s, and the convention is “James’ car” because it’s easier to say and write.

What I find interesting is that we don’t contract “Jane’s car” as “Jane’r car” from “Jane, her car.”

Maybe it goes back to that Parlement decision to use masculine pronouns.

Fred’s slacks, etc.”

‘s is how all possession is made apparent, except in the case of the pronoun “it.” “Its” is the proper way to spell the possessive, “it’s” is the contraction for “it is.”

Even in Canada.

And if you want to make a shelf unit to hide a secret room or passage, try this one:
http://pervivere.blogspot.com/2005/09/holly-shelf-unit-batman.html

And if you want a fortress house, try this one: http://www.oneofakindhouse.com/fortress.html

Fred’s slacks, etc.