A profit a prendre may, like an easement, be acquired by either grant or prescription. Since the grant of such a right involves a transfer of an interest in land, it must be created by writing, and a seal is necessary to the validity of the grant at common law.40 An attempted grant of a profit a prendre, if invalid as being merely oral, or, it would seem, as wanting a seal, creates a license merely, which may be revoked at any time,41 but by reason of

36. Stockbridge Iron Co. v. Hudson Iron Co., 107 Mass. 290; Massot v. Moses, 3 Rich. (S. C.) 168; Harlow v. Lake Superior Iron Co., 36 Mich. 105; Silsby v. Trotter, 29 N. J. Eq. 228; Grubb v. Bayard, 2 Wall. Jr. 81, Fed. Cas. No. 5,849; Funk v. Halde-man, 53 Pa. St. 229; Mountjoy's Case, Co. Litt. 164b.

37. See Brown v. Spilman, 155 U. S. 665, 39 L. Ed. 304; Union Petroleum Co. v. Bliven Petroleum Co., 72 Pa. St. 173; Duffield v. Rosenzweig, 144 Pa. St. 520, 2.' Atl. 4.

38. See Stockbridge Iron Co. v. Hudson Iron Co., 107 Mass. 290, 322; Kamphouse v. Gaffner, 73 111. 453; Neumoyer v. Andreas,

57 Pa. St. 446; Boone v. Stover, 06 Mo. 430; Silsby v. Trotter, 29 N. J. Eq. 228; East Jersey Iron Co. v. Wright, 32 N. J. Eq. 248; Painbridge, Mines (5th Ed.) 280 et seq.; Macswinney, Mines, c. 12. and authorities cited, ante, Sec. 254.

39. Ante, Sec. 381, notes 14-16.

40. Hopkins v. Robinson, 2 Lev. 2; Somerset v. Fogwell, 5 Barn. & C. 875; Holford v. Bailey, 13 Q. B. 426; Taylor v. Millard, 118 N. Y. 244, 6 L. R. A. 667, 23 N. E. 367; Kamphouse v. Gaffner, 73 I11. 453; Boone v. Stover, 66 Mo. 430; Mcbee v. Loftis, 1 Strob. Eq. (S. C.) 90.

41. Williams v. Morrison (C. C.) 32 Fed. 177; Wheeler v. West, 71 Cal. 126, 11 Pac. 871; Kampthe making of improvements by the intended grantee on the faith thereof the intending grantor may be estopped to deny the validity of the grant,42 as in the case of an invalid grant of an easement.43

A profit a prendre may also, like an easement, be created by words of exception or reservation.43a

A right of profit may be acquired by prescription, provided the taking during the prescriptive period was limited to the requirements of a particular dominant tenement.44 But there can be no prescriptive right of profit in the public45