c anonymous master of the roll power to make lease grandfather father and son  the grandfather be seize of a estate upon the marriage of the father settle it  to the father for life remainder to the first and other son of the father in  tail successive c with power to the father to make lease not exceed three life  or twentyone year which power extend only to lease in possession the father  after his marriage have issue several son make a lease for three life to his  young son of a estate which be freeman then in lease so that at law this lease  be a reversionary lease be void and the question be whether it shall be  support in equity and it be decree that the young son shall hold and enjoy  during the lease it be a provision for a child and he take these difference  upon power saint difference between a power create by act of parliament which  shall always be take strict and equity will not help it but if it be void at  law it be void in equity but where it be create by the act of the party there  in the case of a purchaser or of a provision for a child although the power be  not strict pursue equity will help it post c p at least to make it good so far  as it may have be good by virtue of the power if it have be duly execute as  where there be a power to make lease for twentyone year and the party lease  for thirty this will be make good in equity for twentyone Harvey v Harvey  Barnard in case of a provision for a child or a purchaser d difference where a  lease be make pure voluntary and no provision for a child there if the lease  be not good at law it shall never be make good in equity but if a lease be  make to a tenant at a rackrent without a fine which be voluntary yet if the  tenant have be at any considerable expense in such case the tenant may at  least as against the party contract to grant the lease fair be consider as a  purchaser see do v weller t r Shannon v Bradstreet l Sch and Lef but see as to  the interest of those in remainder Blore v Sutton Meriv post c p in building  or improve there this court will supply the defective execution of the power  but otherwisenot freeman er p