And be it enacted, that in every conveyance of lands to be made by the promoters of the undertaking under this or the special Act the word “dispone” shall operate as a clause of absolute warrandice by the promoters of the undertaking, for themselves and their successors, or for themselves, their heirs, executors, administrators, and assigns, as the case may be, to the respective disponees therein named, and the successors, heirs, executors, administrators, and assigns of such disponees, according to the quality or nature of such conveyances and of the F1right or interest therein expressed to be thereby conveyed, except so far as the same shall be restrained or limited by express words contained in such conveyance.