*361 Mr. Justice Brown,

after stating the case, delivered- the opinion of the court.

1. This case was referred by consent tp Mr. Harrison, a so-called “ master commissioner,” as referee, with ‘ instructions to report the testimony, with the findings of fact and of law, to the court. The fact that no such officer "as master commissioner is known to the law does not impair the validity of the reference, as it is. perfectly competent for the court to refer a case to a priyate. person. Heckers v. Fowler, 2 Wall. 123. And, as the court in its judgment ordered his findings to stand as the findings of the court, the only questions before this court are whether the facts found by the referee sustain the judgment, As the case was not tried by the Circuit Court upon a waiver in writing of a trial by jury, this court cannot review exceptions to the admission or exclusion of evidence, or to findings of fact by the referee, or to his refusal to find facts as requested. Roberts v. Benjamin, 124 U. S. 64; Boogher v. Insurance Co., 103 U. S. 90; Bond v. Dustin, 112 U. S. 604; Paine v. Central Vermont Railroad Co., 118 U. S., 152; Andes v. Slauson, 130 U. S. 435 .

. There are eighteen assignments of error, but as most of them are taken to the action of the referee, they need not be further noticed. . :

2. The court below was of opinion that the contract in question was a several one as between Shipman and the three other parties, and hence that an action would lie in favor of either of these parties without joining the .others. Three separate actions were in fact brought against him. There is nothing in the contract indicating that the three parties were connected- in any way, except that each, was to furnish an equal quantity of coal. They are spoken of in the contract as “ the other three parties,” as if it were intended that each of them should stand for himself. If either of them had failed to furnish his quota of coal, Shipman might have brought an action against him; but it is clear that if he had .sued them jointly for such default, the two others might answer that they had done all that they agreed to do, and *362 could not be held liable for the default of the third. These parties did not agree to furnish any definite amount of coal, but merely that they would ship the defendant the product of their mines in equal quantities. Separate orders were given by. Shipman, and separate bills were rendered by the companies for coal shipped upon such orders; and there is nothing to indicate that either of the parties to the contract treated it as involving a joint liability. Hall v. Leigh, 8 Cranch, 50. If Shipman had settled with plaintiff according to the account rendered by it in this case, it seems to us that it could not be' seriously contended that the other parties could not sue him for the coal furnished by them without joining the plaintiff.

3. The principal controversy in this case, however, grows out of that clause of the contract which requires of Shipman “ that he will turn in all his present trade and orders on their coal at the price of 70 cents per ton at the mines.” In this connection, the referee asked the advice of the court, as to whether this meant that the three companies should furnish coal at 70 cents per ton at the mines, to fill only such orders and contracts as Shipman then had, (June 24, 1879,). for immediate delivery of coal; or, that they should furnish it at that price to fill all such contracts and orders, whether for immediate or future delivery; or, whether they should furnish it to fill all contracts which Shipman then had, or might thereafter make, before the market price of coal advanced, with parties who had previously been, customers of his; and, whether this was limited to those who were previously customers of his or not.

The-fourth question put by the referee was whether, viewing all the provisions of the contract, • the companies were required.to furnish Shipman coal.to fill contracts made by him for future delivery at the market price of coal in Detroit at the time Shipman made such contracts, and not at the ■price at the time such coal was actually delivered by the plaintiffs to Shipman from time to time during the existence of such contracts.

The court answered the third question that the clause quoted included all contracts and orders, which Shipman then *363 had, whether for the immediate or future delivery of coal, but did not bind the companies to fill contracts made by Ship-man subsequent to June 24, at 70 cents per ton. It at first answered the fourth question, that the three companies were bound to furnish Shipman coal to fill contracts made by him for future delivery, at the market price of coal, at Detroit at the time Shipman made such contracts, and not at the market price at the time of the delivery of such coal by the. companies to Shipman, from time to time, during the existence of such contracts. Upon the basis of these answers, the referee found a balance of $230.74 due from the defendant to the plaintiff, with interest from August 1, 1880.

Exceptions were taken by both parties to the report of the referee, when the court, reaffirming, its answers to the first, second, and third questions, reached the conclusion that the answer to the fourth question was wrong, and that the true answer was that, excepting contracts within the designation of “present trade and orders,” which the contract of June 24, 1879, required Shipman to turn in at the price of 70 cents per ton at the mine, the three companies named' in thp contract were not bound to furnish him coal to fill contracts made by him for future delivery at the market price of coal at Detroit at the time when Shipman made such contracts, but that they were entitled to the market pricé at the date of the áctual'sale of.such.coal by them to Shipman, less his “fair proportion” of any advance in the price, as specified in the contract.

In determining the correct answer to this question, it is proper to consider the situation of the parties and the surrounding circumstances. For some years prior to June 24, •1879, defendant Shipman had been extensively engaged in the business of buying and selling coal in the Detroit market, and had from time to time purchased considerable coal for that market from the plaintiff. The two other, parties to the contract had also, prior to such date, established a coal office in Detroit and competed with Shipman for the Detroit trade. At the date of this written contract, and for some time before and since then, there existed at Detroit a usage or custom *364 among coal dealers and their larger customers to make contracts for the sale and delivery of coal at a stipulated price for the year next ensuing, and this usage or custom was known to all the parties to this contract when they entered into it. At the date of this contract the price of lump coal was 70 cents,- and of nut coal 25 cents per ton, at the mines. After the execution of this contract- the three respectively shipped coal to defendant at Detroit, and to his customers on his orders, and separate accounts were kept both by Shipman and the plaintiffs respectively of the coal shipped by each. Monthly bills Were rendered by them respectively to defendant, in which they charged for the. coal shipped prior to October 1,1879, at the rate of 70 eents for lump and 25 cents for nut coal, and for all coal, both lump and nut, shipped after October 1, 1879, bills were rendered to defendant at the market price, which was largely in excess of 70 and 25 cents. There appears to have been a slight advance in coal at the mines some time in July or August, and in the account rendered in August by the plaintiff, defendant was charged 75 cents per ton for lump coal. Efe palled the attention of the company to the fact, and the company, in the September accóúnt, credited, the defendant with the 5 cents per ton overcharge.

As the contract made no mention of .the price'to be charged, except so far as concerned coal furnished, to fill orders in exist1 énqp at the time of the contract, it would follow that the plaintiff was at liberty to charge the defendant the current market price at the mines at the time of each delivery. In view, however, of the custom of the coal trade at Detroit to make contracts for the sale and delivery of coal at a stipulated, price, for the year next ensuing,- and in view of the fact that this custom was known to all the parties to this contract at the time .they entered into it, it may fairly be presumed that the contract was- made with reference to that custom. The fact-that the companies reserved to themselves the power to inspect defendant’s books, sales, and contracts for coal at all times, while the contract remained in force, is somewhat inconsistent with the idea thát they had! no interest in any *365 contracts made by him after June 24, and only contemplated selling him at the market price. The fact that he had agreed to labor to improve the market price of coal, giving the other parties the advantage of whatever improvement might be made in the market, to which the companies were to lend their aid and encouragement, tends to show that the relations between them were different from those between an ordinary vendor and vendee. Indeed, the fact that the contract provides that he was to represent the entire interests and sales of the companies in the Detroit trade; that he could only sell soft coal received from them; that he was to labor .for the improvement of the market, and if he succeeded in raising the price, that he was-to receive only a fair proportion of such increase, indicates rather the relation of partners or of principal and agent than that of vendor and vendee. If this were the case, the companies would be bound by his contracts, made within the scope of his authority and according to the custom of the Detroit trade. It can hardly be supposed, under this contract, that if Shipman were to make an agreement, say July 1, 1879, to deliver one thousand tons during the next year at a given price, and coal was to rise immediately thereafter, he would be obliged to pay the companies the increased price, and still sell to his customers at the contract price — in other words, to sustain the whole loss himself; inasmuch as he was representing their interests in Detroit, was obliged to submit to them his books and contracts for their inspection, and in case of an improvement in the market was obliged to account to them for their fair proportion of the increase. On the other hand, if coal fell after the contract was made, and it had proved to be a profitable one, it would seem to have been the expectation of the parties that he should only receive his fair proportion of such profit.

It is unnecessary to characterize or define this contract or to say whether it creatéd the relation of vendor and vendee, principal and agent, or a partnership, as it possesses some features characteristic of each of them. But, although it is very ambiguous and indefinite, and was evidently not drawn *366 by any one learned in the law, we think the answer first given by the court to the fourth question corresponds better with its tfrue meaning and intent, and that the companies were bound to furnish defendant coal to fill contracts for future delivery at the market price of coal in Detroit at the time he made such contracts.

So far as Shipman’s “ fair proportion ” of an increase is concerned, we see no distinction between nut and lump.

This covers all the questions properly raised by the record in this case, and the result is that the judgment of the court below must be

Reversed, and the case remanded for further proceedings in conformity with this opinion.

Me. Justice Gray was not present at the argument and took no part in the decision of this case.