Couple of words in a Court of Session document

[goldie61]

This is from a document in the Court of Session at National Records of Scotland.

Just a couple of words here .They are underlined in the document - not by me.

The case concerns a weaver who impersonated another weaver to get his work. This is an appeal by the manufacturers to not have to pay him.

...Letters in Russels name which
are ready to be produced 3tio
In all Contracts betwixt
Master and Servant there
is a De?    ?  We
accordingly chose and
engaged Russel for our
workman so that if another ..


The ‘3tio’ I take as '3rd’ - it is the third point the manufacturers have made for their case against him.

Any ideas?
Thanks

[Flattybasher9]

delectus personae

Malky

[GR2]

In Scots law, delectus personae (choice of person) is the right of selection of a particular person to occupy any specific position. The legal importance of this is that the person so chosen is prevented from delegating the position or assigning it to someone else.

[rossko57]

Lawyers throwing Latin about, I would say the guess that 3tio is equivalent to third is good (would tritio be appropriate here?)

[CarolA3]

More likely 'tertio'?

Carol

[goldie61]

Many thanks everybody for your replies. 
I thought it must have been a Latin term I didn't recognise - thanks for the explanation GR 2. Add it to the list!