1. The nature of the obligation.

2. The person to whom the obligation is made.-Nullity, however, under this head, is predicated only when the promisee is mistaken by the promisor for another person ; not when he has the very person in mind whom his language indicates, and when his mistake is in assigning to such person unreal qualities. Of the latter class of mistakes the following stages are noticed: A promise is made to a party who gives an erroneous Christian name; to a party who gives an erroneous family name; to a party who gives the name of another person of whose existence the person promising is not aware; to a party who gives the name of another person whose existence is known to the promisor, or is accepted by him as existing. In the last case, an error as to the person, strictly speaking, cannot be said to exist any more than in the first; but the constituents of personality in the last case are essential, while in the other cases they are non-essential.

3. The object of the obligation. If this object is defined quantitatively, then a material variance as to quantity is error that avoids.1.

1 As to liability for negligence see infra, sec 1043.

4. So far as concerns the incidents of the obligation, a distinction is to be taken between such as according to existing business standards constitute the essence of the object, and such as do not.-If the promisor erroneously assigns to the object properties of the first class, then his declaration, as relating to something which essentially, if not corporeally, he did not have in mind, is a nullity. An error, on the other hand, as to properties of the second class, does not avoid this obligation.2 An error, for instance, as to the metal of which a vase is composed, brass being mistaken for gold, is essential, and avoids the bargain, the particular kind of metal being here material; whereas, an error as to the particular kind of wood used for a bucket-e. g., pine or hemlock-is not essential, and does not avoid, unless the contract be for some reason dependent on the kind of wood used. The question whether, when the object of a promise has been injured, its essential properties are changed, depends, therefore, in default of a special bargain, on the particular case.3.

The supremacy of Savigny's doctrine is, however, by no means unchallenged. By eminent recent critics4 not only is the accuracy of Savigny's commentary on the authorities disputed, but the rule that essential error avoids is declared to be subject to so many exceptions as to be practically nugatory. These exceptions are: (1) Negotiable paper, bills of lading, etc., are governed, as to third parties, by their words, irrespective of the question of error. (2) A "foreign captain" gives signals of distress by mistake, but under such circumstances as make it highly probable that such signals would be given by him. A steam-tug is sent to him with a pilot, but he rejects the proffered aid, and arrives safely in port. In the mean time another ship, from this cause losing the services of the pilot and tug, runs ashore. The "foreign captain"1 would be liable under the port laws for the expenses of the pilot and tug, notwithstanding he acted under an essential mistake. And this is undoubtedly true, though not necessarily on the ground of contract, since the captain in such case would be liable for negligently making signal. (3) Registrator X., to take another case,2 likes " Manzipan" (a kind of German cake), and dislikes macaroons (Makronen). In order to be sure he himself writes the order to the confectioner, but is surprised at finding a macaroon-tart on the table. It is sent back, but the confectioner produces the order, "Makronentorte," signed by Mr. X. Now Mr. X.'s "error in essence" would be no defence to a suit against him on this order.-Another case is as follows: "C. Eicken," during the French-German war, receives an order to buy, in Posen, a large amount of oats at any price. He executes the contract, but, as he is about to forward the oats, he finds that the order was meant not for him, but for "F. Eicken." The party sending the order refuses to accept the oats, which in the mean time have greatly fallen.-In another case a house is offered for rent, according to the written terms, at 1800 marks, payable quarterly, at end of term. As the lessee is about to move in his furniture, the lessor refuses admission on the ground that he did not mean what the writing said, and that it contained two clerical errors: " 1800" for "2800," and "postnum" for "praenum."-Now, in such cases, it would not be pretended that the party from whom the writing proceeds is not bound by the writing. This was substantially ruled in Germany in a famous case,1 in which a telegraphic message had in it "buy" instead of "sell."-It is maintained that the common sense view of such transactions is that a party is to be bound by what he writes. It is urged, also, that the whole doctrine of consent, as taught by Savigny, rests on the erroneous hypothesis that it is intention and not expression that constitutes a legal act. This is admitted to be the case with wills, in which the voluntas testatoris is to prevail. It is otherwise with contracts; and, in contracts, the party accepting takes the will of the other as expressed. This is what is relied on by the promisee ; and the promisee acts in consideration of the equivalent that is to be given him for the services called for in the other party's proposal. The error of the prevalent view, so it is insisted, is, that, while it seeks to maintain without restriction the right of the party mistaken to do as he really intends, it allows him to invade at his pleasure the rights of others and subject them to his undeclared and arbitrary will. If this were carried out-if the burden of a mistake fell, not on the party making it, but on the other party-then all business security would be destroyed. An order by telegram could not be tilled without inquiry to see whether or no it was not made under a mistake, and to these inquiries there might be no end ; or indemnity might be exacted, which would add greatly to the burdens of the transaction.-The reply to this, that a party-making a mistake in a written order is liable for culpa in contrahendi)? and in this way he is made to pay the losses incurred by the other side through his conduct, is anticipated by Bekker, who makes in answer the following points: (1) the remedy on the contract is more simple and effective; (2) to have recourse to culpa in contrahendo is to unnecessarily introduce penal remedies into civil jurisprudence.-This is undoubtedly ingenious; but it should not cause us to overlook the fact that, when the parties do not agree as to the object of their bargain, there can be no contract. If I should intend, for instance, to sell a house; and the other party should intend to buy a ship, there is no agreement between him and me. This, however, does not preclude my liability to him for culpa in contrahendo in case he is damaged by my inaccuracy of expression.1 In our own law, it is also to be observed, the doctrine of estoppel comes in to impose a liability in such cases on a party who, although not bound by force of a specific contract, is precluded by his conduct from denying his liability to a party whom he has induced to assume certain obligations. -The distinction between essential and non-essential error is also discussed by Scheiff in a treatise elsewhere noticed.2 In bilateral obligations, error, according to Scheiff, precludes consent in two cases: (1) where with either party there is an essential variance between intention and expression; and (2) when in consequence of error the expressions of the parties do not go to the same thing. - Savigny's view is also contested in a work published, in 1880, by Dr. Emil Pfersche.3 Error in substance, it is argued, is simply an error of judgment, and does not involve a variance between intention and expression. The party bargaining under this error intends what he says; and if the other party says the same thing, then there is a concurrence of the two minds. This is sustained by a copious examination of the Roman standards, which, however, are often subjected, in order to support the author's argument, to forced and unnatural constructions; and while there is no doubt much truth in the position taken by him that error in substantia does not necessarily involve a variance between intention and expression, yet it does in most instances involve a variance between the intentions of the two contracting parties. He further argues, that errors as to the properties of a thing, essential or unessential, are always errors in motive.-The declaration, "I buy this thing," is a normal expression of will, no matter what may have been the mistake of the party as to the properties of the thing. It is true, he admits, the Romans assimilated error in substantia to error in corpore. But this was not from the false theoretic stand-point that error in substantia was of the same class as error in corpore, but from practical considerations. Nullity in such cases was not a logical necessity, but an arbitrary fiction, in order to obtain for the purchaser a safeguard, the condictio pretii. In such cases, as, through the condictio pretii, the vendor was indemnified from loss, and as between the two theories the only diffe-rence was, whether the purchase-money was to be obtained by the condictio or by the actio emti, the question was merely pro-cessuel, having no practical consequence, and hence is not discussed on principle by the classical jurists. The rule they laid down was that the purchaser, whether the contract was a nullity or an existing fact, was entitled to recover the price of an article which was deficient in material properties he believed on good grounds and without negligence to belong to it. The old doctrine of nullity in case of essential misapprehension was only thrown out speculatively ; was of no practical consequence; and should have no place, as in itself unreasonable, so it is argued, in the Roman common law. By that law, justice is fully done through the rule of warranty, express and implied, that it lays down (Gewahrleistung). The vendor is held for properties which he knew or ought to have known the purchaser believed the goods to possess, and he is obliged, if these properties fail, to return the price pro tanto.- In an article by Brandis,1 an authoritative contemporaneous German jurist, the prevailing doctrine in Germany is stated now to be, that error as to the juridical nature of a transaction is always essential, but that error as to a person is only essential when the intention was directed specifically to such person, and error as to properties of a thing (Eigenschaften) is only essential when the contract was made on account of such properties. This view is reiterated by Windscheid, in an edition of his commentary published in 1880, and by Ihering, in an essay published in 1881.2 Notwithstanding, therefore, the ingenious and plausible criticisms to which it has been subjected, the doctrine that essential error by either of the parties precludes a contract still holds its supremacy in German jurisprudence. Whatever apparent failures of justice may arise from maintaining this view are compensated for by the application of estoppel in cases where a party inequitably attempts to repudiate an engagement into which he negligently led another, and by making him independently liable in such cases in a suit for negligence.1