The essence of prescription as a means of acquiring ownership or an interest is long-continued use. If the claimant's task were simply the proof of the use and that it had been open, it would not be a difficult one. The chief difficulties are encountered in establishing that the use had the necessary quality of adverseness. The like requirement as to a possession that ripens into ownership under the statute of limitations has its problems, but they are, generally speaking, not so troublesome.