See my post on the Scobie board, and James Dick's about the falling out in the family, the extra b, and mining vs. farming.
http://boards.ancestry.com/mbexec/message/an/surnames.scobbi...I've posted a couple of photos of a titlepage of a 1837 published book with one b Scobie signatures by, I think, my ancestor George Hill Scobbie born 1819 (dated 1841 and 1840) and signatures by John Scobbie also spelt with one b dated 1839 and Nov 1st 1839 (at Cleland). I expect this is James Dick's ancestor John Scobbie (G.H.'s elder brother) born 1802. the book is A Key to Lennie's Principles of English Grammar "intended for Ladies, Junior Teachers, Private Students". G.H would be 20-ish and John would be 37ish, a little old. But if it were signed by G.H.'s cousin and John-1802's son, born 1828, he'd be only 11, which is too young to use the book.
Each name is signed twice, with quite apparent differences in style.
To this message I attach photos of names and dates from George Hill's son James's family bible.