This section is from the book "The Law Of Real Property and Other Interests In Land", by Herbert Thorn Dike Tiffany. Also available from Amazon: A Treatise on the Modern Law of Real Property and Other Interests in Land .
Not infrequently the courts have asserted the view that a thing cannot be a fixture if merely placed on the land, and not actually attached to the land, or to some structure which is itself so attached to the land as, in a legal sense, to form a part thereof.66 In other cases, however, an article of a heavy and permanent character has been regarded, under the circumstances, as constituting a fixture, though merely laid upon the land and kept in place by the force of gravity.67
Occasionally a thing which is not actually attached to the land, and which is not even in its proper or intended place thereon, is regarded as a part of the land because an integral part of or accessory to a structure or appliance which is annexed, such a thing being sometimes referred to as being "constructively annexed."67a
66. Horn v. Baker. 9 East, 215; Wansbrough v. Maton, 4 Adol. & E. 884; Brown v. Lillie, 6 Nev. 244; Williamson v. New Jersey Southern R. Co., 29 N. J. Eq. 311; Walker v. Sherman, 20 Wend. (N. Y.) 636; Hoyle v. Plattsburgh & M. R. Co., 54 N. Y. 314, 13 Am. Rep. 595; Teaff v. Hewitt, 1 Ohio St. 511, 59 Am. Dec. 634; Hill v. Wentworth, 28 Vt. 429. See authorities cited in Ewell, Fixtures (2d Ed.) 18; 13 Am. & Eng. Enc. Law (2d Ed.) 600.
67. Stockwell v. Campbell, 39 Conn. 362, 12 Am. Rep. 393; Bleth-en v. Towle, 40 Me. 310; Sheppard v. Blossom, 66 Minn. 421, 61 Am. St. Rep. 431, 69 N. W. 221; Snedeker v. Warring, 12 N. Y. 170; Doscher v. Blackiston, 7 Ore. 143; Holland v. Hodgson, L. R. 7 C. P. 334; Monti v. Barnes  1 K. B. 205. So buildings merely resting on a wooden foundation have occasionally been regarded as fixtures. (Landon v. Platt, 34 Conn. 517; Ogden v. Stock, 34 111. 522, 85 Am. Dec. 332; Madigan v. McCarthy, 108 Mass. 376, 11 Am. Rep. 371), as have fences resting on the surface of the ground (Glidden v. Bennett, 43 N. H. 306; Wentz v. Fincher, 34 N. C. (12 Ired. Daw) 297, 55 Am. Dec. 416; Kimball v. Adams, 52 Wis. 554, 38 Am. Rep. 756, 9 N. W. 170). See 13 Am. & Eng. Enc Law 603. In Pennsylvania the requirement of actual physical attachment has been positively repudiated. Voor-his v. Freeman, 2 Watts & S. (Pa.) 116, 37 Am. Dec. 490; Seeger v. Pettit, 77 Pa. 437, 18 Am. Rep. 452.
67a. See Goodrich v. Jones, 2 Hill (N. Y.) 142; Byrne v. Werner, 138 Mich. 328, 69 L. R. A. 900, 110 Am. St. Rep. 315, 101 N. W. 555.
A part of a machine, temporarily removed, either for the purpose of repairs or safe keeping, or in order to facilitate a particular use of the machine, has been considered to come within this principle,68 though it may perhaps, in most cases, be as well regarded as having become part of the realty by reason of actual annexation, and as not having ceased to be so because temporarily severed.69 Keys, doors, and windows, have been regarded as part of the realty on the same theory,70 though they also might ordinarily be regarded as actually annexed. Even railroad engines and cars have occasionally been held to be fixtures,71 but the best-considered cases regard them as personal property, they being without the fixity of location which, with few if any exceptions, is an essential characteristic of a fixture.72 In a few cases this theory of constructive annexation has been applied to the case of articles brought upon the land with the intention of attaching them thereto, but not yet actually attached.73
68. Ex parte Ashbury, 4 Ch. App. 630; Sheffield & South Yorkshire Permanent Bldg. Soc. v. Harrison, 15 Q. B. Div. 358; Bain v. Brand, 1 App. Cas. 762; Fisher v. Dixon, 12 Clark & F. 312; Dudley v. Hurst, 67 Md. 44, 8 Atl. 901, 1 Am. St. Rep. 368; Hopewell Mills v. Taunton Sav. Bank, 150 Mass. 519, 6 L. R. A. 249, 15 Am. St. Rop. 235, 23 N. ed. 327; Wad-leigh v. Janvrin, 41 N. H. 503, 77 Am. Dec. 780.
69. See 13 Am. & Eng. Enc. Law, 615; Ewell, Fixtures, 62; Bronson, Fixtures, Sec.Sec. 18 c (5) 24.
70. Liford's Case, 11 Coke, 50 b; State v. Elliot, 11 N. H. 540; Hill v. Wentworth, £8 Vt. 436.
71. Booth v. Central Sav. Bank, 58 Colo. 519, 146 Pac. 240; Palmer v. Forbes, 23 111. 301; Farmers' Loan & Trust Co. v. Hen-drickson, 25 Barb. (N. Y.) 484; Elizabethtown, R. & P. Co. v. Elizabethtown, 12 Bush. (Ky.) 233. See Minnesota Co. v. St. Paul Co, 2 Wall. (U. S.) 609, 17 L. Ed. 886, and note.
72. Hoyle v. Plattsburgh & M. R Co., 54 N. Y. 314; Williamson v. New Jersey Southern R Co., 29 N. J. Eq. 311; Coe v. Columbus, P. & I. R. Co., 10 Ohio St. 372; Chicago & N. W. Ry. Co. v. Borough of Ft. Howard, 21 Wis. 44. The nature of rolling stock is fixed by statute in a number of states. 1 Stimson's Am. St. Law, Sec. 468.
73. McLaughlin v. Johnson, 46 111. 163; Geppalt v. Middle West Stone Co., 94 Kan. 560, 146 Pac.
In some cases the courts have considered the mode of physical attachment as decisive that the article attached is a part of the land,74 hut the tendency is to consider this as in itself but a slight indication that the article is a fixture, provided it is susceptible of removal without injury to the land, or to the structure constituting: a part of the land to which it is attached.75 The fact, however, that a chattel is so attached to a structure that its removal would leave an unfinished gap in the structure has been regarded as strong evidence that the chattel has become a part of the land.76