It has been decided that if one who has an easement in another's land gives a license to the owner of the servient tenement to do something thereon, the effect of which is to obstruct the exercise of the easement, and the licensee, on the faith of the license, makes expenditures for improvements obstructive of the easement, the easement is extinguished.75 Accordingly, if one entitled to an ease70. Rhodes v, Whitehead, 27 Tex. 304, 84 Am. Dec. 631.

71. See Veghte v. Raritan Water Power Co., 19 N. J. Eq. 142. Pratt v. Sweetser, 68 Me. 344; Angell, Water Courses (7th Ed.) Sec. 252, note; 3 Kent, Comm. 450, note by Mr. Justice Holmes. The distinction is not recognized in England. See Gale, Easements, 527. In Hale v. Oldroyd, 14 Mees. & W. 789; Ward v. Ward, 7 Exch. 838; Lovell v. Smith, 3 C. B. (N. S.) 120, - all cases of prescriptive easements, - nonuser lor the statutory period was not regarded as in itself extinguishing the right, no reference being made to any such distinction as that referred to above.

72. California Civ. Code, Sec.

Exercise, is thereafter estopped to deny the validity of the release. If he evidently does not intend to release the easement, as when he gives permission to construct merely a temporary obstruction, the fact that such obstruction is erected would apparently not preclude him from afterwards asserting the easement.80

811; Montana Codes 1907, Sec. 4517; North Dakota, Comp. Laws 1913, Sec. 5340. Oklahoma Rev. Laws 1910, Sec. 6633; South Dakota Civ. Code, Sec. 277.

73. Cox v. Forrest, 60 Md. 74; Wilder v. City of St. Paul, 12 .Minn. 192; Corning v. Gould, 16 Wend. (N. Y.) 531.

74. See Reg v. Chorley, 12 Q. B. 515; Moore v. Rawson, 3 Barn. & C. 332; Louisville, & N. R. Co., v. Covington, 2 Bush (Ky.) 526; Fitzpatrick y. Boston, & M. R. R., 84 Me. 33, 24 Atl. 432. Canny v. Andrews, 123 Mass 155; Steere v. Tiffany, 13 R. I. 568.

75. Winter v. Brockwell, 8 East, 308, as explained in Hew-ilns v. Shippam, 5 Barn. & C. 221; Liggins v. Inge, 7 Bing. 682; ment of light over another's land gives a license to the owner of the servient tenement to erect a building thereon which will prevent the passage of light, and the building is erected accordingly, the easement of light is extinguished;76 and, if one entitled to flow another's land gives such other a license to erect an embankment preventing such flow, and the embankment is erected, the easement of flowage is extinguished.77 These decisions have been referred to in some jurisdictions as representing an exception to the general rule that a license is revocable even though followed by improvements on the faith thereof,78 but they may more satisfactorily, it is conceived, be regarded as applications of the doctrine of estoppel. Just as one who undertakes orally to grant an easement is, after the intended grantee makes improvements on the strength thereof, estopped to deny the validity of the grant,79 so one who undertakes orally to release an easement by authorizing the construction of improvements which will prevent its

Boston, & P. R. Corp. v Doherty, 154 Mass. 314, 28 N. E. 277; Cart-wright v. Maplesden, 53 N. Y. 622; Addison v. Hack, 2 Gill (Md.) 221, 41 Am. Dec. 421; Vogler v. Geiss, 51 Md. 407. Davidson v Kretz, 127 Minn. 313, 149 N. W. 652. See Stein v. Dahm, 96 Ala. 481, 11 So. 597.

76. Winter v. Brockwell, 8 East, 308. The doctrine has been held to be applicable to the so-called easements of light, air, and access in the owner of land abutting on a highway. White v. Manhattan Ry. Co., 139 N. Y. 19, 34 N. E. 887. See Post, Sec. 417.

77. Morse v. Copeland, 2 Gray (Mass.) 302.

78. "The authorities * * * show that the rule, sometimes laid down in the books, that a license executed cannot be countermanded, is not applicable to licenses which, if given by deed, would create an easement, but to licenses which, if given by deed, would extinguish or modify an easement. They also show that the distinction, sometimes taken in the books, between a license to do acts on the licensee's own land, and a license to do acts on the licensor's land, is the same distinction that is made between licenses which, if held valid, would create, and licenses which extinguish or modify, an easement." Metcalf, J., in Morse v. Copeland, 2 Gray (Mass.) 302. 79. Ante, Sec. 349(d) notes 44-49.

Attention has,80a in this connection, been called to the consideration that, after the obstruction has been erected on the servient tenement under license from the owner of the dominant tenement, the latter is powerless to remove it or to compel its removal, and that this in itself precludes him from again exercising the easement until the owner of the servient tenement voluntarily removes the obstruction, or it is removed by natural causes.

In the case of a license to obstruct a way at a particular point only, the fact of the construction of the obstruction in accordance therewith, while it may properly be regarded as extinguishing the way at that point, and, by reason of the physical conditions of the way, such partial extinguishment may necessarily involve a total disuse of the way,81 it may occur that a right of passage by or around the obstruction is substituted by agreement,82 with the result that the way still exists over the servient tenement except at the point at which the obstruction occurs.83 The fact that, without having given any express license to obstruct the way, the owner of the dominant tenement makes no objection to the erection of a structure which has that effect, does not necessarily, it seems, preclude him from

80. See Vogler v. Geiss, 51 Md. 407.

80a. See editorial note, 11 Columbia Law Rev. at p. 78.

81. See Vogler v. Geiss, 51 Md. 407; Cartwright v. Maples-den, 53 N. Y. 622; Aldrich v. Billings, 14 R. I. 233; Boston & P.

R. Corp. v. Doherty, 154 Mass. 314, 28 N. E. 277; Davidson v. Kretz, 127 Minn. 313, 149 N. W. 652.

82. Ante, Sec. 367, notes 12-17.

83. See Peck v. Lloyd, 38 Conn. 566; Hall v. Hall, 106 Me. 389, 76 Atl. 705.

Afterwards asserting bis right of passage if the owner of the servient tenement knew, or had reason to know, of the easement.84 But the physical conditions of the way and the other circumstances may be such as to justify an inference that another place of passage has been substituted by mutual assent.85