delivered the opinion of the Court.

This suit was brought by the appellee, to recover on an alleged acceptance of the appellant, of an order on the latter from Gwinn & Co. for the payment of whatever should become due on a contract between that firm and the appellant, for the manufacture of certain car-fenders. The contract referred to was created by two letters ; one dated the twelfth day of February from Gwinn & Co. to the appellant, in the words following : “ We will be pleased to furnish you with one hundred, more or less, complete fenders, equipments for the Washington and Georgetown Railway Company, for twenty-five dollars net per car. This will include two wheel-guards and one automatic projecting fender for each car, also equipping cars with the same ; ” the other, dated the next day, from Blakistone, “Your proposition for the manufacture of I oo fenders for the Washington and Georgetown Railway Company, dated Febry. 12th, 1895, is hereby accepted.”

On the 29th March, 1895, Gwinn & Co. gave to the appellee an order on the appellant “ for all moneys which may become due under the above contract, after deducting five hundred dollars already paid on account thereof.” This order was not presented to the appellant for acceptance until the twenty-second day of May following, when Blakistone accepted in writing, in the terms following : “ The within order is hereby accepted, less amount already advanced at this date, about nine hundred and twenty-five dollars.”

The appellant now claims the right to a credit for other sums paid by him to Gwinn & Co. after the date of the acceptance, but admits a liability of four hundred and fifty dollars and twenty-four cents, which he has paid into Court. This right, it is contended, arises from the fact, that by reason *314of a verbal agreement between the appellant and Gwinn & Co., he was bound to make advances of money to Gwinn.. & Co. to enable them to complete the work on the fenders ; that at the time of his making the acceptance the appellee was informed of this agreement, and verbally promised, that if the appellant would accept the order, in consideration thereof, it would make such advances to Gwinn & Co. as-were required of the appellant; and that the appellee having failed to perform its part of the agreement, the appellant was at liberty to make the advances, and deduct the amount of them, from whatever might become due on account of the acceptance.

All evidence was admitted subject to exceptions, and at. its conclusion the appellee moved the Court to strike out and exclude from the jury, first, all testimony offered, to prove that such verbal, agreement was made between the parties hereto, and secondly, all testimony offered to prove the verbal agreement between the appellant and Gwinn & Co. Bo.th of these motions were granted by the Court, and the propriety of so doing presents the first question to be now considered.

Was the evidence offered to establish the alleged verbal agreement between the appellant and Gwinn & Co., proper to go to the jury? It appears from the evidence, that the appellant had received from the Washington & Georgetown Railway Company a proposition to equip their cars with the fenders, of which he was the patentee, at a cost of $3 5 per car. The appellant testifies, that not knowing what the cost of fenders would be, if built elsewhere than in his own shops,. “ he sent for Mr. Gwinn of C. L. Gwinn & Co., whom he knew was desirous of making them, and told him * * to look over the cars of the railroad company and make up his mind for what price he could put the fenders complete on the cars in Washington later on, Gwinn returned, and said he could do the work for twenty-five dollars per car. The appellant said, he thought the price too low, that they could not be made for that sum. Gwinn then stated he *315“ was better equipped for making fenders and could make a profit at that price.” The appellant then “ told Gwinn, that another matter to be considered ” was, had he “ the facilities and money to carry on the contract;” to which. Gwinn replied, that he had, “ the only thing I ask of you is that when I ask you from time to time to give me something on account to help out my pay-roll, you will do it.” The appellant said “ he would help him, that he had no-objection to giving him a little money as the work progressed to meet current expenses ; that he also told him to put the offer in writing, which was done as set out.” This is a brief summary of that portion of the testimony, that most strongly supports the contentions of the appellant. We have stated-it at large, because we think it will enable us to arrive at the true meaning of the parties. The appellant was looking about for a machinist to manufacture the fenders ; he sends, for Gwinn to get an estimate of the cost from him and if practicable to employ him. When the price is given him,, he seeks to be satisfied that they can be made for the sum mentioned, as his own “ price” with the railway company “ must depend upon the price set by Gwinn.” Being assured on this point, another matter concerns him ; has. Gwinn “ the facilities and money to carry on the contract.” Gwinn tells him he has, but may have to ask him from time for “something” to help out his pay-roll. This possible, obstacle having been thus removed, he tells Gwinn to put his. offer in writing, which is accordingly done in the letter already quoted. From this brief analysis of the proof, it must be apparent, that there is no indication of an intention on the part of either the appellant or the appellee, to enter into a contract with respect to advances. That-something was said about advances is true, but they are referred to only as connected with the financial ability of Gwinn & Co. about which the-appellant desired to be satisfied, before he entered into contractual relations with them. But apart from this, the terms of the alleged agreement are too vague and uncertain to give rise to a legal obligation. The words are “ the only-*316thing I ask you is that when I ask you from time to time to give me something on account to help out my pay-roll, you will do it,” and the appellant replies “ he would help him.” Now construing this alleged agreement in the most favorable way for the appellant, it leaves to the appellant the absolute right to determine the amounts of the advances and the necessity and times when they are to be made. Such a contract is too vague and uncertain to confer any rights whatever upon Gwinn & Co., enforceable either in law or equity. Thomson v. Gortner, 73 Md. 482; Taylor v. Brewer, 1 M. & S. 290; Roberts v. Smith, 4 Hurl. & N. 315; American and English Enc. of Law, vol. 3, 842. For these reasons, we are of opinion there was no evidence sufficient to enable the jury to find a verbal agreement between the appellant and Gwinn & Co., which bound the former to make advances to the latter, during the progress of the work on the fenders, and the Court committed no error in excluding the testimony offered to prove it.

It maybe remarked here, that the defendant's first, second and third prayers, which were rejected by the Court below, are all based upon the theory, that there was evidence before the jury from which they could find that the contract between Gwinn and Company and the appellant required the latter to make advances to the former to complete the contract. In view of what has already been said it follows that the assumption of such a theory cannot be maintained. All of these prayers were therefore properly refused.

The proof also shows, that the consideration passing from the appellee to Gwinn & Co. for the order on the appellant was a loan on $1,500, made about the time the order bears date.^ At the time of its presentation to the appellant for acceptance, it is contended, an agreement was entered into between the appellant and the appellee the effect of which was to bind the appellee, in consideration of the acceptance, to make advances to Gwinn & Co. to enable them to complete their contract. This contention rests entirely upon the evidence of the appellant, and we will give what he *317states, in his own language. He testifies that Mr. Schultz (the president of the appellee), came to his office on the 22nd of May, and presented the order. The appellant after stating he had given Gwinn and Company a considerable amount of money since the date of the order, further said, “Mr. Schultz, I have no objection to protecting your bank to the extent of whatever is due Mr. Gwinn under this contract whenever the money is to be paid, but if I accept this order, Mr. Gwinn having been steadily calling on me for money, unless you or somebody is going to take care of him, he will never complete this order, for he has only three or four cars completed in Washington.” He said, “ Well, I suppose somebody will have to take care of him, I suppose we will have to do it, we have always helped Mr. Gwinn, and I suppose we will have to take care of him.” I said, “ If you take care of him, then I have no objection to undertaking to pay you what is due him, when the contract is completed.” I sat down to write it (the acceptance) myself and his exact language to me, was, “ Have you any objection to putting in the amount you have advanced up to this time ;” I said, “No, and I wrote at the bottom, ‘About $925 * * * ’ Mr. Schultz left there with that acceptance.”- On motion, this evidence was excluded by the Court from the consideration of the jury.

The general principle is familiar, that parol evidence is not admissible to qualify the terms of a written instrument; it being conclusively presumed, “ that such writing expresses the entire contract, and all evidence of previous colloquium or understanding must be excluded.” Delamater v. Chappell, 48 Md. 244. It therefore cannot be successfully contended (nor has it been in this case), that this evidence is admissible for the purpose of establishing a co-temporaneous agreement under which the appellant was to pay the appellee another or different amount than that called for by the order and its acceptance. Ought it to have been admitted to establish a parol agreement independent of, collatex-al to and distinct from the wnfittexi acceptance ? If the *318evidence would warrant the finding of such an agreement it ought to have gone to the jury to enable them to determine what the contract was. Roberts & Co. v. Bonaparte, 73 Md. 198. But the question is, is this evidence of such a .character? Could the jury, if they had been in possession of it, have reasonably and legally found that the acceptance was signed by the appellant, by reason of a valid legal promise on the part of the appellee, to make the advances ? It is clear, unless the evidence is such as will warrant such ■ a conclusion, it should not have been admitted; and in that ■event the whole case would rest upon a proper construction of the terms of the acceptance. Now it must be borne in mind that on the 22nd of May, the situation was such that -both the appellant and appellee were deeply interested in the ability of Gwinn & Co. to complete their contract with respect to the fenders. The appellant had agreed to furnish ■the railway company with one hundred fenders at thirty dollars per car, and Gwinn & Co. had undertaken to manufacture them at twenty-five dollars per car. The appellant •had already advanced to the extent of $925, though he was ■under no legal obligation to do so, in order to assist Gwinn & Co. in the completion of their work. On the other hand, the appellee had loaned them fifteen hundred dollars, and to secure the re-payment of this sum, had taken an order for such sum as might become due under their contract with Blakistone. If Gwinn & Co. failed to complete their work ■the appellant would suffer, if not lose, on his contract with the railway company; and since nothing would then be due • to Gwinn & Co. from the appellant, the order and the ac- ■ ceptance thereon would become valueless. In the light of these circumstances, it cannot be successfully maintained •'that the conversation already stated, in which the parties seem to have done nothing more than recognize and refer to the situation as it actually existed, can amount to a solemn engagement, or was intended to have the force and ■effect of varying, if not annulling the terms of the written ■ acceptance. It may be true, that the appellant supposed *319the appellee, under all the circumstances, would make advances to Gwinn & Co., indeed, he testified to that effect; but notwithstanding his belief, there is not enough in the •conversation to amount to a contract, or to justify a jury in finding that Mr. Shultz bound the appellee to make the .advances. In fact there is no promise, express or implied, to that effect. The appellant did not require such a. promise as a condition precedent to his signing the acceptance, but seems to be satisfied with the declaration that •somebody will have to take care of Gwinn, and “he supposed they would have to do it.” Anson on Contracts, page 22. But even if this were-otherwise, the loose terms employed '■by the parties are not sufficient to constitute a valid contract. To “take care of Gwinn,” even though the words be limited in their application to the completion of the Tenders, is exceedingly indefinite. Do they mean that the . appellee is to loan him money ? if so, to what extent ? or under what circumstances ? Who is to determine these questions upon which the obligation of the appellee must be made to depend ? A Court should not allow loose expressions, such as this, to go to the jury for the purpose of ■raising obligations and rights between parties. Thomson v. Gortner, 73 Md. 475; Delashmutt v. Thomas, 45 Md. 140; Recknagle v. Schmals, 33 N. W. (Iowa) 365; Taylor v. Brewer, 1 Maule & S. 290; Roberts v. Smith, 4 Hurl. & N. 315.

In the last case cited the plaintiff agreed to accept the ■ appointment of secretary at a salary of Ü300, “ if the com-pany be completely registered and put into operation ; if not, I shall be satisfied with any renumeration for my time and labor you may think me deserving of and your means ■ can afford.” The defendant replied, “ it is distinctly agreed, * * if the company be not formed that part of your letter which alludes to your salary be null and void, and that . at the expiration of three months it is entirely left to me to give you such sum of money as I may deem right as compensation * * in the event of the company not being *320carried out.” The plaintiff rendered service but the company was not formed. It was held, there was “ a liability in honor and not a liability by contract.” In Guthing v. Lynn, 2 B. & A. 234, where the alleged contract was, that if the “ horse proved lucky ” the plaintiff should give five pounds more, Lord Freeberdren said, these words were “too loose and vague to be considered in a Court of law,” * * that they amounted “ merely to one of those honorary engagements which seem very much to prevail among persons in this way of business.” So in Sherman et al. v. Ketsmiler et al., 17 S. & R. 47, the Court said, “if a promise is so vague in its terms as to be incapable of being understood or of being carried into effect, it cannot be enforced.”

It follows from what has been said, there was no error in rejecting the evidence.

The defendant’s fourth prayer is based on the theory that the appellant was at liberty to make the required advances to Gwinn to carry out their contract, provided they were made after Gwinn & Co. became insolvent and unable to complete the contract, and after the refusal of the appellee. We have already said, if the appellee did not bind itself by a valid contract to make advances to Gwinn & Co. its right as against Blakistone depended alone on a proper construction of the terms of the order and its acceptance. We have held that Blakistone was under no legal obligation to “ carry Gwinn & Co.,” and even if this were otherwise, there was no undertaking on the part of the appellee to take his place in that respect. In view of this, the well established doctrine that imposes upon a party the duty in certain situations of minimizing loss, has no application whatever. The appellee had a right to stand upon the terms of the order and acceptance. The granting of the plaintiff’s first prayer and the rejection of the defendant’s fourth was therefore proper. We do not find error in the modification made in the defendant’s fifth prayer. The judgment must be affirmed.

Judgment affirmed with costs.