Conclusiones ex tit. D. de rei vindicatione

41. For either the joined things are homogeneous, or of the same nature, or heterogeneous, or of a different nature.
42. If they are homogeneous, and confusion a mixing of liquids has occurred, so that one substance penetrates the other—for instance, if my gold is mixed with your gold, or my silver with your silver—we say that in this case, whether the confusion happened with or without our consent, a communion of the thing has been created. Thus, any part of the mixed gold or silver belongs to both of us, and therefore an action for the division of common property, or even a claim for one's own part in proportion to the weight, will be granted.
43. For a claim for the body of the thing cannot be made precisely because separation is impossible.
44. The same obtains if the union has been made through ferruminatio welding of like metals, but not if through plumbatura soldering with lead.
45. We call ferruminatio the solidifying and joining of materials of the same kind; but plumbatura is the gluing together of any materials whatsoever, which is done by lead alone.
46. But if, in things of the same nature, it is not confusion but commixtio the mixing of solids that has occurred, so that one substance does not penetrate the other—as if my grain were mixed with yours—we say it matters whether that happened by the will of both, or by one only, or by chance.
47. In the former case, the will and consent of the owners creates a communion, and therefore it will be handled by the action for the division of common property.
48. In the latter, a claim is given to each for his own part, since each person's thing continues in its own substance.
49. If, however, in this case also, separation is difficult, the office of the judge can intervene so that each person's part is returned to them in proportion to the measure.
50. But if heterogeneous or diverse things are joined, a distinction is made again.