51. (1) The following books shall be kept in the several offices hereinafter named, namely:- A-In all registration offices- Book 1, “Register of on-testamentary documents relating to immoveable property”; Book 2, “Record of reasons for refusal to register”; Book 3, “Register of wills and authorities to adopt”; and Book 4, “Miscellaneous Register”; B-In the offices of Registrars- Book 5, Register of deposits of wills.” (2) In Book 1 shall be entered or filed all documents or memoranda registered under sections 17, 18 and 89 which relate to immoveable property, and are not wills. (3) In Book 4 shall be entered all documents registered under section 18 which do not relate to immoveable property. (4) Nothing in this section shall be deemed to require more than one set of books where the office of the Registrar has been amalgamated with the office of a Sub-Registrar. (5) If, in the opinion of the Registrar, any of the books mentioned in sub-section (1) is in danger of being destroyed or becoming illegible wholly partially, the Registrar may, by a written order, direct such book or portion thereof as he thinks fit, to be recopied and authenticated in such manner as may be prescribed by rules, and the copy prepared and authenticated under such direction shall, for all purposes of this Act and of the Evidence Act, 1872, be deemed to be the original book or portion and all references in this Act to the original book shall be deemed to be to the book or portion so recopied and authenticated.