The old gentleman could not at first bring the circumstance to his recollection, but on mention of the Portugal piece of gold the whole returned upon his memory.

He made an immediate search for the papers and recovered them, so that Mr.Rutherford carried to Edinburgh the documents necessary to gain the cause which he was on the verge of losing." The story is reproduced because it is clearly one of the tales which come round in cycles, either because events repeat themselves or because people will unconsciously localise old legends in new places and assign old occurrences or fables to new persons.

Thus every one has heard how Lord Westbury called a certain man in the Herald's office "a foolish old fellow who did not even know his own foolish old business".

Lord Westbury may very well have said this, but long before his time the remark was attributed to the famous Lord Chesterfield.

Lord Westbury may have quoted it from Chesterfield or hit on it by accident, or the old story may have been assigned to him.
In the same way Mr.Rutherford may have had his dream or the following tale of St.Augustine's (also cited by Scott) may have been attributed to him, with the picturesque addition about the piece of Portuguese gold.