The New International Encyclopædia…
“ By act of union between England and Scotland (5 Anne, ch. 8) , one great seal for the United Kingdom of Great Britain is used for sealing writs to summon Parliament, for treaties with foreign States, and all public acts of State affecting Great Britain. The holder of the great seal is still the Lord Chancellor. A seal is also kept in Scotland for sealing grants and writs affecting private rights there. As regards Ireland, the Act of Union (39 and 40 George III., ch. 67) provided that various acts, as to summoning Parliament, etc., should be done under the great seal of the United Kingdom ”
