for the thing itself. But here an important question arises, namely, whether the jurisdiction of equity will depend upon the nature of the thing contracted for, or upon the views and intentions of the person who contracts for it in the particular case. If it depends upon the former, it is a question of law, and it should be the subject of settled rules; if it depends upon the latter, it is a question of fact, and hence the fact must be tried as often as the question arises. Unfortunately, the question cannot be answered unqualifiedly either way; but, for the most part, the jurisdiction of equity undoubtedly depends upon the nature of the thing contracted for. To make it depend upon the actual views and intentions of one of the contracting parties would be subject to two very serious objections: first, that the decision of the question of jurisdiction would involve a ruinous expense both to the parties and to the public; secondly, it would involve an inquiry which a court of justice can seldom enter upon with much chance of getting at the truth, and which, therefore, it should never enter upon except from necessity. Upon the whole, it may be said that the jurisdiction will depend exclusively upon the nature of the thing contracted for, wherever the court can see its way to laying down an absolute rule; but where it cannot, it would be too much to say that all evidence as to the views and intentions with which the thing was contracted for in the particular case will be excluded.
In what cases, then, will equity assume jurisdiction over a contract which consists in giving a specified thing on account of the nature of the thing? It will do so, first, whenever the thing is land, or any interest in land, or any incorporeal thing material to the enjoyment of land; secondly, whenever the thing is a vessel, or any interest in a vessel;[1] thirdly, whenever the thing is a chattel for which no substitute can be obtained, or for which a substitute can be obtained only with great difficulty. It must be confessed that this last rule is somewhat vague; but we must choose between a vague rule and no rule at all. Unfortunately, also, there are but few precedents by which the application of this rule can be illustrated. One reason of this will doubtless be found in the peculiar rule of our law respecting the sale of chattels (other than vessels); namely, that the moment that a contract is made for the sale of a chattel, the title to the chattel passes from the seller
