It appears somewhat singular that no question has ever been judicially suggested as to whether a party wall agreement of the character referred to is not invalid under the Rule against Perpetuities. If the agreement in effect provides that the ownership of part of the wall is to change at an indefinite time in the future, as stated in the cases last referred to, it is difficult to see why such provision is not within the rule. And even apart from such a provision for a change in the ownership of the wall, if the right of the non builder, or of his successor in interest, to use the wall, is dependent on the payment by him of part of the cost, a construction of the agreement which is sometimes adopted,39 such an attempt to create an easement to arise at some indefinite time in the future would seem to be within the rule.40 Conflict with the rule could be entirely avoided, it is conceived, by considering the part of the wall erected on the non builder's land as continuing to be the property of the builder even after user and payment therefor by the former, or as being from the first the property of the person on whose land it stands, and by furthermore considering the agreement as immediately creating cross easements in the land of each proprietor, with a contractual liability on the part of the non builder as regards part of the cost of the wall.

37. Maine v. Cumston, 98 Mass. 317; Berry v. Godfrey, 198 Mass. 228, 84 N. E. 304; Hill v. Huron, 33 S. Dak. 324, 145 N. W. 570.

38. Mickel v. York, 175 111. 62, 51 N. E. 848; Kuh v. O'reilly, 261

111. 437, 104 N. E. 5; Nat. Life Ins. Co. of Montpelier v. Lee, 75 Minn. 157, 77 N. W. 794; Glover v. Mersman, 4 Mo. App. 90; Masson's Appeal, 70 Pa. St. 26.

It has occasionally been suggested that such an agreement creates the relation of vendor and purchaser as regards that part of the wall placed on the non builder's land,41 that it, in other words, creates an option in the non builder to purchase that part of the wall. Such a construction of the agreement would not protect it from the operation of the Rule against Perpe39. As apparently in Masson's Appeal, 70 Pa. 26; Conner v. Joy, - Tex. Civ. App. - , 150 S. W. 485. But not in Matthews v. Dixey, 149 Mass. 595, 5 L. R. A. 102, 22 N. E. 61; Hill v. Huron, 33 S. Dak. 324, 145 X. W. 570.

40. Gray, Perpetuities, Sec. 316.

41. See Gibson v. Holden. 115 111. 199, 56 Am. Hep. 146, 3 N. E. 282; Mcchesney v. Davis, 86 111. App. 380; 8 Columbia Law Rev. at p. 121.

Tuities,42 and it does not appear to be adopted in practice, a conveyance of that part of the wall not being executed upon payment by the non builder of part of the cost, as we might expect to be done if such payment involved the consummation of a purchase. Furthermore, while such an option would involve in effect a contract or covenant by the builder to convey to the non builder the part of the wall on the latter's land, when ever the latter may desire to use the wall, upon payment by the latter of the stipulated part of the cost, yet the possible existence of such a contract or covenant on the part of the builder is ignored in the numerous cases discussing whether the benefit or burden of the agreement to pay for the land wall pass to successors in title.43 In view of this omission to refer to any such contract or covenant in this connection, in which it would most properly be referred to, it seems reasonable to conclude that the theory that the parties stand in the relation of vendor and purchaser as regards the wall has not been generally adopted.

A party wall agreement of the character referred to, involving as it does the creation of easements in land, is invalid if merely oral.44 If, however, the wall is erected in accordance with the agreement, the parties are, it appears, in the same position as if the agreement had been originally valid. The agreement involves an attempted oral grant by one proprietor to the other of an easement to place the wall in part on the former's land, which is, on the theory of part performance or estoppel,45 validated by the subsequent construction of the wall on the faith thereof.46 Such grant can, how42. Gray, Perpetuities, Sec.Sec. 330-330c.

43. Post, Sec.Sec. 393,

44. Tillis v. Treadwell, 117 Ala. 445, 22 So. 983; Rice v. Roberts, 24 Wis. 461, 1 Am. Rep. 195; Hodgkins v. Farrington, 150

Mass. 19, 5 L. R. A. 209, 15 Am. St. Rep. 168, 22 N. E. 73.

45. Ante, Sec. 349(d), notes 44-49.

46. Rawson v. Bell, 46 Ga. 19; Russell v. Hubbard, 59 111. 335; Wickersham v. Orr, 9 Iowa, 253, ever, be recognized and enforced only subject to the conditions and stipulations to which it was originally subject, including the right of the grantor to make use of the wall upon the payment by him of part of the cost thereof. So far as concerns the personal liability of such grantor under his contract to pay a portion of the cost of the wall in case of its use by him, conceding that such contract is within the Statute of Frauds, which appears somewhat questionable, it is validated, it seems, by reason of the part performance involved in the building of the wall,47 and apart from the doctrine of part performance, the user of the wall, since this belongs to the builder thereof, would involve a liability in tort or upon the theory of quasi contract. That a contract to pay a certain sum in case one makes a particular use of another's property is invalid under the statute can not enable him to make such use of the property without incurring any liability.

If the proprietor who, by the terms of the agreement, is to construct the partition wall on the division line between the two properties, fails to extend it the full length of that line, the other, it has been held, has the privilege of so extending it.48

What constitutes a user of the wall by B which will render him liable under his covenant to A, who constructed the wall, for part of the cost thereof, is primarily a matter of the construction of the covenant. A user of the wall in the course of the reconstruction of an existing building, as distinguished from its use in the erection of a new building, has, in particular cases, been regarded as insufficient to impose a liability.49 And a like view has been taken of the erection by B of another wall impinging upon the wall built by A, although the existence of this latter wall enables B to make his wall of lighter construction.50 In one case a covenant to pay part of the cost of the wall when the covenantor used it was construed to involve an obligation upon his part to use the wall in a reasonable time,51 and in two cases the court appears to have construed such a covenant as involving a liability upon the covenantor if he conveyed his land and so put it out of his power to use the wall.52

74 Am. Dec. 348; Horr v. Hollis, 20 Wash. 424, 55 Pac. 565; Miller v. Brown, 33 Ohio St. 547.

47. See Rawson v. Bell, 46 Ga. 19; Rindge v. Baker, 57 N. Y. 209; Stuht v. Sweesy, 48 Neb. 767, 67 N. W. 748; Swift v. Cal-nan, 102 Iowa, 206, 37 L. R. A. 462, 63 Am. St. Rep. 443, 71 N. W. 233; Rice v. Roberts, 24 Wis. 461, 1 Am. Rep. 195.

Occasionally the user of the wall by the proprietor who did not build it has been regarded as a performance which takes his contract to pay a part of the cost out of the statute. Walker v. Shackelford, 49 Ark. 503, 4 Am. St. Rep. 61, 5 S. W. 887; Pireaux v. Simon, 79 Wis. 392, 48 N. W. 674.

48. Matthews v. Dixey, 149 Mass. 595, 22 N. E. 61; Negus v. Becker, 72 Hun (N. Y.) 479, 25 N. V. Supp. 640.