Webster’s 1913 has no entry under this spelling.
Shades of meaning
Fernald has no entry of its own for sworn statement; he lists it under oath.
Where he writes about it:
In the highest sense, as in a court of justice, "an oath is a reverent appeal to God in corroboration of what one says," ABBOTT Law Dict.; an affidavit is a sworn statement made in writing in the presence of a competent officer; an adjuration is a solemn appeal to a person in the name of God to speak the truth. — from oath