18. The law also makes provision for the performance of the ecclesiastical duties of a benefice by curates in the case of an incumbent who does not reside thereon for nine months in each year and does not with the consent of the bishop perform the ecclesiastical duties while residing on another benefice of which he is the incumbent, or while holding a licence not to reside on the benefice or not to reside in the parsonage house thereof.[95] 19. Incumbents who are non-resident with the bishop's licence cannot without the bishop's permission resume the duties of their benefice before the expiration of their licence; nor can they, if non-resident for more than twelve months, interfere during that period with the curate entrusted with those duties by the bishop.[96] 20. In reckoning the periods prescribed by law as to non-residence, a month is a calendar month, except where it is to be made up of an aggregate of lesser periods, in which case thirty days are to be deemed a month. A year is to be reckoned as commencing on January 1, and ending on the following December 31, both inclusive.[97] 21. An incumbent vacates his benefice by (i.) death, (ii.) resignation, (iii.) admission to other preferment which he cannot by law hold therewith, or (iv.) deprivation. 22. Resignation must be tendered to the bishop, and unless made in view of an exchange must be unconditional. It should be made either in person or by a deed attested by two witnesses. The presence and attestation of a notary in addition are usual but are not essential. The resignation may be made at the request of the bishop to avoid scandal and legal proceedings, and he may agree to postpone the declaration of the vacancy to a fixed date in the future in order to enable the incumbent to receive the tithe rentcharge accruing before that date. Its acceptance by the bishop need not be signified in any particular form or even in writing, and is implied if the resignation was tendered at the bishop's request. It cannot be revoked after its acceptance by the bishop. Whether it can, under any circumstances, be revoked previously to acceptance by him is not clear.[98] If, however, it is made for the purpose of an exchange, it does not take effect unless the exchange is carried out; so that if either of the exchanging incumbents dies before being inducted to his new living, both resignations are void, as well as the institution and induction of the other to the deceased's old living, if that has taken place.[99] The Benefices Act, 1898, precludes an incumbent, when he is presented, from entering into any engagement for resigning the benefice except under the Clergy Resignation Bonds Act, 1828, sects. 1, 2, which allow such an engagement with a view to the appointment to the benefice, when resigned, of a single specified individual whomsoever, or of one of two specified individuals, each of whom is by blood or marriage an uncle, son, grandson, brother, nephew,