the courts； so far as I am aware； do not sanction it； and certainly did not in this instance。
There is another ground for holding the charter…party void and no contract； instead of regarding it as only voidable； which is equally against authority； which nevertheless I have never been able to answer wholly to my satisfaction。 In the case put； the representation of the lessor of the vessel ＇330＇ concerned the vessel itself； and therefore entered into the description of the thing the lessee agreed to take。 I do not quite see why there is not as fatal a repugnancy between the different terms of this contract as was found in that for the sale of the barrels of salt described as containing mackerel。 Why is the repugnancy between the two terms；first； that the thing sold is the contents of these barrels； and； second； that it is mackerelfatal to the existence of a contract？ It is because each of those terms goes to the very root and essence of the contract； /1/because to compel the buyer to take something answering to one； but not to the other requirement； would be holding him to do a substantially different thing from what he promised； and because a promise to take one and the same thing answering to both requirements is therefore contradictory in a substantial matter。 It has been seen that the law does not go on any merely logical ground； and does not hold that every slight repugnancy will make a contract even voidable。 But； on the other hand； when the repugnancy is between terms which are both essential； it is fatal to the very existence of the contract。 How then do we decide whether a given term is essential？ Surely the best way of finding out is by seeing how the parties have dealt with it。 For want of any expression on their part we may refer to the speech and dealings of every day； /2/ and say that； if its absence would make the subject…matter a different thing； its presence is essential to the existence of the agreement。 But the parties may agree that anything； however trifling； shall be essential； as well ＇331＇ as that anything； however important； shall not be； and if that essential is part of the contract description of a specific thing which is also identified by reference to the senses； how can there be a contract in its absence any more than if the thing is in popular speech different in kind from its description？ The qualities that make sameness or difference of kind for the purposes of a contract are not determined by Agassiz or Darwin； or by the public at large； but by the will of the parties； which decides that for their purposes the characteristics insisted on are such and such。 /1/1 Now； if this be true； what evidence can there be that a certain requirement is essential； that without it the subject…matter will be different in kind from the description； better than that one party has required and the other given a warranty of its presence？ Yet the contract description of the specific vessel as now in the port of Amsterdam； although held to be an implied warranty； does not seem to have been regarded as making the contract repugnant and void； but only as giving the defendant the option of avoiding it。 /2/ Even an express warranty of quality in sales does not have this effect； and in England； indeed； it does not allow the purchaser to rescind in case of breach。 On this last point the law of Massachusetts is different。
The explanation has been offered of the English doctrine with regard to sales； that； when the title has passed； the purchaser has already had some benefit from the contract； and therefore cannot wholly replace the seller in statu quo； as must be done when a contract is rescinded。 /3/ This reasoning ＇332＇ seems doubtful； even to show that the contract is not voidable； but has no bearing on the argument that it is void。 For if the contract
is void； the title does not pass。
It might be said that there is no repugnancy in the charterer's promise； because he only promises to load a certain ship； and that the words 〃now in the port of Amsterdam〃 are merely matter of history when the time for loading comes； and no part of the description of the vessel which he promised to load。 But the moment those words are decided to be essential they become part of the description； and the promise is to load a certain vessel which is named the Martaban； and which was in the port of Amsterdam at the date of the contract。 So interpreted； it is repugnant。
Probably the true solution is to be found in practical considerations。 At any rate； the fact is that the law has established three degrees in the effect of repugnancy。 If one of the repugnant terms is wholly insignificant； it is simply disregarded； or at most will only found a claim for damages。 The law would be loath to hold a contract void for repugnancy in present terms； when if the same terms were only promised a failure of one of them would not warrant a refusal to perform on the other side。 If； on the other hand； both are of the extremest importance； so that to enforce the rest of the promise or bargain without one of them would not merely deprive one party of a stipulated incident； but would force a substantially different bargain on him； the promise will be void。 There is an intermediate class of cases where it is left to the disappointed party to decide。 But as the lines between the three are of this vague kind； it is not surprising that they have been differently drawn in different jurisdictions。
＇333＇ The examples which have been given of undertakings for a present state of facts have been confined to those touching the present condition of the subject… matter of the contract。 Of course there is no such limit to the scope of their employment。 A contract may warrant the existence of other facts as well； and examples of this kind probably might be found or imagined where it would be clear that the only effect of the warranty was to attach a condition to the contract； in favor of the other side； and where the question would be avoided whether there was not something more than a condition；a repugnancy which prevented the formation of any contract at all。 But the preceding illustrations are enough for the present purpose。
We may now pass from undertakings that certain facts are true at the time of making the contract； to undertakings that certain facts shall be true at some later time；that is； to promises properly so called。 The question is when performance of the promise on one side is a condition to the obligation of the contract on the other。 In practice； this question is apt to be treated as identical with another； which； as has been shown earlier； is a distinct point； namely； when performance on one side is a condition of the right to call for performance on the other。 It is of course conceivable that a promise should be limited to the case of performance of the things promised on the other side； and yet that a failure of the latter should not warrant a rescission of the contract。 Wherever one party has already received a substantial benefit under a contract of a kind which cannot be restored； it is too late to rescind； however important a breach may be committed later by the other side。 Yet he may be ＇334＇ excused from going farther。 Suppose a contract is made for a month's labor； ten dollars to be paid down； not to be recovered except in case of rescission for the laborer's fault； and thirty dollars at the end of the month。 If the laborer should wrongfully stop work at the end of a fortnight； I do not suppose that the contract could be rescinded； and that the ten dollars could be recovered as money had and received； /1/ but； on the other hand； the employer would not be bound to pay the thirty dollars； and of course he could sue for damages on the contract。 /2/
But； for the most part； a breach of promise which discharges the promisee from further performance on his side will also warrant rescission； so that no great harm is done by the popular confusion of the two questions。 Where the promise to perform on one side is limited to the case of performance on the other； the contract is generally conditioned on it also。 In what follows； I shall take up the cases which I wish to notice without stopping to consider whether the contract was in a strict sense conditioned on performance of the promise on one side； or whether the true construction was merely that the promise on the other side was limited to that event。
Now； how do we settle whether such a condition exists？ It is easy to err by seeking too eagerly for simplicity； and by striving too hard to reduce all cases to artificial presumptions； which are less obvious than the decisions which they are supposed to explain。 The foundation of the whole matter is； after all； good sense； as the courts have often said。 The law means to carry out the intention of the parties； and； so far as they have not provided ＇335＇ for the event which has happened； it has to say what they naturally would have intended if their minds had been turned to the point。 It will be found that decisions based on the direct implications of the language used； and others based upon a remoter inference of what the parties must have meant； or would have said if they had spoken； shade into each other by imperceptible degrees。
Mr。 Langdell has called attention to a very important principle； and one which； no doubt； throws light on many decisions。 /1/ This is； that； where you have a bilateral contract； while the consideration of each promise is the counter promise； yet prima facie the payment for performance of one is performance of the other。 The performance of the other party is what each means to have in return for his own。 If A promises a barrel of flour to B； and B promises him ten dollars for it； A means to have the ten dollars for his flour； and B means to have the flour for his ten dollars。 If no time is set for either act； neither can call on the other to perform without being ready at the same time himself。
But this principle of equivalency is not the only principle to be drawn even from the form of contracts； without considering their subject…matter； and of course it is not offered as such in Mr。 Langdell's work。
Another very clear one is found in contracts for the sale or lease of a thing； and the like。 Here the qualities or cha