This quality depends on several different circumstances, which have little connexion with each other.  One part of a compound object may become more considerable than another, either because it is more constant and durable; because it is of greater value; because it is more obvious and remarkable; because it is of greater extent; or because its existence is more separate and independent.  It will be easy to conceive, that, as these circumstances may be conjoined and opposed in all the different ways, and according to all the different degrees, which can be imagined, there will result many cases, where the reasons on both sides are so equally balanced, that it is impossible for us to give any satisfactory decision.  Here then is the proper business of municipal laws, to fix what the principles of human nature have left undetermined.

The superficies yields to the soil, says the civil law:  The writing to the paper:  The canvas to the picture.  These decisions do not well agree together, and are a proof of the contrariety of those principles, from which they are derived.

But of all the questions of this kind the most curious is that, which for so many ages divided the disciples of Proculus and Sabinus.  Suppose a person shoued make a cup from the metal of another, or a ship from his wood, and suppose the proprietor of the metal or wood shoued demand his goods, the question is, whether he acquires a title to the cup or ship.  Sabinus maintained the affirmative, and asserted that the substance or matter is the foundation of all the qualities; that it is incorruptible and immortal, and therefore superior to the form, which is casual and dependent.  On the other hand, Proculus observed, that the form is the most obvious and remarkable part, and that from it bodies are denominated of this or that particular species.  To which he might have added, that the matter or substance is in most bodies so fluctuating and uncertain, that it is utterly impossible to trace it in all its changes.  For my part, I know not from what principles such a controversy can be certainly determined.  I shall therefore content my self with observing, that the decision of Trebonian seems to me pretty ingenious; that the cup belongs to the proprietor of the metal, because it can be brought back to its first form:  But that the ship belongs to the author of its form for a contrary reason.  But however ingenious this reason may seem, it plainly depends upon the fancy, which by the possibility of such a reduction, finds a closer connexion and relation betwixt a cup and the proprietor of its metal, than betwixt a ship and the proprietor of its wood, where the substance is more fixed and unalterable.]