§ 308. When certificate must be under seal. 1. When a certificate of acknowledgment or proof is made without this state, whether within or without the United States, (a) if made by a judge or other presiding officer of a court having a seal, or by the clerk or other certifying officer thereof, such certificate must be under the seal of such court; (b) if made by a commissioner of deeds appointed pursuant to the laws of this state to take acknowledgments or proofs without this state, such certificate must be under his seal of office; (c) if made by any officer specified in subdivision one of section three hundred one of this chapter, such certificate must be under the seal of the legation or consulate to which such officer is attached.

2. Any certificate, required by the provisions of section three hundred eleven of this chapter to be authenticated, must be so authenticated, in addition to being under seal as provided in this section.