In some States a deed cannot be recorded unless the signor acknowledges his signature or the signature is proven by a witness. The manner of acknowledgment by an individual is explained fully in the chapter on contracts (page 59). A corporation cannot, of course, acknowledge its signature. Yet the seal must be proven. This is done by the officer who affixed the seal. He is sworn by an officer authorized to take acknowledgments, and on oath states his residence, his official title in the corporation, that he affixed the seal, that the seal affixed is the corporate seal and that he acted by order of the governing board of the corporation. The officer taking the acknowledgment then certifies these facts on the deed and signs it stating his title. (Appendix form 16).