Looking for Peter Grant from Inverness

I am trying to find information about my great-great grandfather, Peter Grant. He was born in Inverness, Scotland, in about 1815. He studied law in Inverness, and came to Canada in 1832, settling in Gainsborough Township, Lincoln County, Ontario. In 1855 or so he married Elizabeth Muir from Sanday, Orkney. They had three daughters and a son. Peter Grant died in Gainsboro Township on April 17, 1890.

Can anyone help me trace his family line back in Scotland?