Easement. An Easement is the right which the owner of one piece of land, technically called the dominant land, has in respect of his ownership, by virtue of which right the owner of another piece of land, technically termed the servient land, is necessitated to allow the owner of the dominant land to do something on the servient land, or something which has relation to that land, or is himself obliged not to do something on that land, and this power possessed by the owner of the dominant land or this duty to forbear on the part of the owner of the servient land, must be something that is for the benefit of the owner of the dominant land. Easements are very numerous, and are classed as public and private; they are principally the right to air, light, common, water, and passage. By the "Prescription Act" passed in the second and third years of the reign of William IV. (2 and 3 William IV. c. 71), an uninterrupted enjoyment of rights or common and all other profits or benefits to be taken and enjoyed from or upon any land for 30 years shall not be defeated except by showing that it was without the knowledge of the adverse party, or that it was by his mere licence or permission, and after an enjoyment of 60 years the claim is indefeasible, except it can be shown that such enjoyment was under consent or agreement in writing.