Adding the names of attesting witnesses, where such addition may in any way change the legal effect of the instrument,1 as where execution may be proved by such witness or by proof of his signature if he is dead or beyond seas,2 or such addition may prolong the period of limitations ;3 or re?noving the name of a subscribing witness placed there orignally,4 is a material alteration to the name of the payee of an instrument which thereby is made negotiable, or changing the words "or order "to " or bearer,"3 or inserting "jointly and severally "4 are material alterations.