ARTICLE II: On Accession

887. Definition. By the name of accession is understood that right by which the owner of the principal thing becomes owner of the accessory thing, i.e. of all things that are produced by some thing of his, or are united to it naturally or artificially.

Division. Accession is either natural, or industrial, or mixed.

I. Natural Accession is had: 1. By birth of animals, when namely from your animal another is born: "for the offspring follows the womb." - 2. By fructification, i.e. production of fruits from land, without human industry. - 3. By alluvion, when by force of waters an increase is added gradually to your estate.

But if a notable part of land is suddenly added, which is called avulsion, its prior owner does not lose ownership if within a useful time he exercises his right.⁰⁴

888. II. Industrial or artificial Accession can happen:

1. By building: when someone builds on his own land from another's materials, or on another's land from his own materials, the building generally belongs to him whose land it is; but with due compensation made to him who built in good faith (III, 500). Nevertheless, concerning this matter, let the laws of each region be consulted.⁰⁵

2. By specification: when a new form or species accedes to preexisting matter, for example if from another's wool you have made a garment, from wood or gold a vessel, from grapes wine.

From old Law, the new species falls to the craftsman, the price of the material being paid, if this material cannot be reduced to the first form, for example a wooden vessel, etc.; and in conscience good faith is more probably required. - Otherwise, the thing falls to the owner of the material, for example a golden vessel (III, 496). See Ami du Cl., 1913, p. 303.

From the new Laws, in either case, the thing falls to the owner of the material, unless the work of the craftsman far exceeds the material in price.⁰⁶

3. By adjunction: when the thing of one is so joined to the thing of another that they make one whole; in which case, the whole composite pertains to him whose thing has itself as principal. Yet this man must make the owner of the accessory part unharmed.

Thus a usufructuary who has painted the walls of a house cannot erase the painting with detriment to the walls. - On the other hand, a painter who has expressed a beautiful image on another's canvas can, with the price of this canvas paid, retain the painted canvas for himself. Thus almost from the law of all.⁰⁷

4. By commixture: when solid things, and by confusion: when liquid things, belonging to diverse persons, are joined.

From the new Laws, the thing becomes common, and, unless something else has been agreed among the owners, must be sold at auction and divided. But if the part of one can be seen as quasi-principal, and otherwise far exceeds the others in price, the owner of this part can vindicate the whole for himself, with the price paid back to the others.⁰⁸

889. III. Mixed Accession happens especially by planting and sowing.

It is called mixed, because two things, i.e. nature and industry, coalesce into one. It is subjected to the same rules to which building is subjected.⁰⁹ Hence the very well-known verse:

Whatever is planted, sown, or built upon,
All yields to the soil, if nevertheless it has taken root.