The railroad company having procured the consent of the authorities of the city to the construction of the railroad in the street or square in question upon the terms agreed upon, such company obtained an interest in and to a certain extent a title to the street for the purposes of the construction and operation of its railroad, which was in the nature of property, and which was sufficient to enable it to treat with abutting property owners in the character of one who had an interest in the servient estate. People v. O' Brien, III N. Y. I.

The case before us is, therefore, different from those cases where an easement has been claimed to have been created in the land of a third person, by reason of his mere license to enter upon his land and do some act of a permanent nature which would amount, if the right should continue, to an interest in the land of such person. This interest in land, the cases hold, requires a grant. In this case the owners of the abutting land had no title to the street. They had an easement in it only, and their consent purported to carry no title to land. There can be no question that they had the right to release, abandon or otherwise extinguish that easement, and upon such terms as they should think fit. The question before us is, whether they have done so and to what extent by the execution of the paper proved upon the trial.

c. A license subsidiary to an interest or valid grant.1 STERLING v. WARDEN. 51 New Hampshire, 217. - 1871. [reported herein at p. 789. ]

d. By equitable estoppel when the licensee has incurred expense in consequence of the fraud of the licensor.2

Jackson & Sharp Company V. The Philadelphia, Wilmington And Baltimore Railroad Company

4 Delaware Chancery, 180. - 1871.

The Chancellor. - The claim made on the part of the complainants to the perpetual use of the side track in controversy as a legal right is based upon two grounds. One of these is, that the right was acquired by contract between their predecessors, - Jackson & Sharp, and the Railroad Company, - the other, that even were there, in the first instance, no contract, but only a permissive use of the track under a license, still, that the license, having been acted upon in the expenditure of large sums of money on the faith of its

1 In these cases there can be no revocation until the entire purpose of the license has been fulfilled and that whether the license be partly executed or wholly executory at the time the revocation is attempted. - Ed.

''In this case and under e below the result of the rule is to give the licensee an interest in the land in most instances as it permits him to maintain permanently any works or structures which he may have erected. - ED.

indefinite continuance, has become irrevocable under the doctrine of equitable estoppel. * * * Let us then proceed to consider the case in the aspect of a license.

On this branch of the case there are several material points upon which no controversy was raised in the argument. One of these is, that the right claimed for the complainant is to an easement or interest in the land of the Railroad Company, the claim being to the perpetual use of the side track as a right appurtenant to the car works, transmissible with the title to them, and binding the land of the company into whosesoever hands it may come, at least so long as it shall be used for the purposes of a railroad. Pitkin v. The Long Island Railroad Company, 2 Barb. Ch. R. 221, is a case very similar. Further, it is agreed that at law an estate or interest in land can be created only by deed or grant under seal, or by prescription, or in this country by twenty years adverse possession or user; in equity such an interest may additionally be acquired by contract, which, however, must, under the statute of frauds, be in writing, subject to an exception of the equity arising out of part performance of a verbal contract. Again, it must be admitted that a license or permission to exercise some privilege upon the land of the licensor can create no estate or interest in the land, such as binds the land and is transmissible from the licensee, the utmost effect of a license being to confer a personal privilege, which is not assignable or transmissible, and is revocable at the licensor's pleasure. Nor does it matter whether the license be by parol or in writing, so long as it remains a mere license, not converted into a conveyance, grant or contract, nor rendered irrevocable by estoppel, as under some circumstances, to be presently noticed, it may be in equity though not at law. Few points have undergone more discussion, and have at length come to be better settled, than the insufficiency of a license at law to create or transfer an interest in land In England the leading cases are Fentiman v. Smith, 4 East, 107; Rex v. Herndon on the Hill, 4 M. & S. 565; Hewlins v. Shippman, 5 B. & C. 221, (E.C. L. 207); Bryan v. Whistler, 8 B. & C. 288 (15 E. C. L. 149); Cocker v. Cowper, 1 C. M. & R. 418, and Wood v. Leadbitter, 13 M. & W. 838, in which last case the prior course of decisions is very fully reviewed. In this country the same rule was adjudged, as early as 1814, by C. J. Parsons, in Cook v. Stevens, 11 Mass. 533. He has been followed in many of the States. Mumfordv. Whitney, 15 Wend. 384; Foot v. The N. H. & Northampto Northampton Railroad Company, 23 Conn. 214; Foster v. Browning, 4 R. I. 47; Den v. Baldwin, 1 Zabriskie, 390; Hays v. Richardson, 1 G. & F. 38; Carter v. Harlan, 6 Md. 20; Bridges v. Purcell, 1 Dev. & Bat. 492.

But it was earnestly urged that although a license is revocable so long as it is executory and the parties remain in statu quo, it ceases to be so, under the doctrine of equitable estoppel, after it has been executed, the licensee having expended money or otherwise involved himself so that he cannot recede without prejudice; that in this case Jackson & Sharp having made large expenditures in erecting and afterwards enlarging their car works upon the faith of their enjoying the continued use of this side track, the railroad company are equitably estopped from revoking the license.