Also, re the Silas'/Silas's question, U.S. style for the possessive form of proper names that end in -s are vague and totally dependent on which one sounds best. Example: We say "Jesus' disciples" for the name Jesus, pronounced with English pronunciation, because it sounds better than "Jesus's disciples." But, but! The Spanish version of the name, Jesús, pronounced "Hay-soos", is quite common in some areas of this country, and the possessive of the Spanish version is more commonly written as Jesús's friends, Jesús's class, Jesús's family, etc.
Is this stuff cool, or what? ;-)