Relationship to me. Great, Great, Great, Great Grandfather. (Maternal)
Again the lack of records appears to be the enemy when researching this era. The only record I could find of James existence is this Memorial Headstone in the Moffat Old Churchyard that was dedicated to a number of the Edgar family.
First there is John whose inscription is shown on his page then follows:
James Edgar, his son, who died at Moffat, 15th. March 1818; aged 59 years Also, Jean Johnson, spouse of the above James Edgar, who died, 25th. March 1814; aged 66 years Also Archbald Edgar, son of John Edgar, who died at Harthope, 3rd. November 1814; aged 11 years, the above John Edgar, died at Moffat 18th. March 1868: aged 88 years. Isabella Aitchison, widow of the above (John) Edgar, who died Academy Road Moffat (–)September (1882) aged 94 years.
It would be highly unlikely that all these people are actually interred under the one headstone.