build, finish, and complete, in a careful, skillful, and workmanlike manner, a complete low-pressure steam-heating and ventilating apparatus, to be furnished and set up in full working order, perfect in all its parts, in the building, so as to fully carry out the design of the work as set forth in the specifications and the plans and drawings of the structure. The building was to be divided into numerous apartments, which were to be arranged and constructed for occupation, and it was evidently the intent of the parties that this should be a complete, and, with proper management, a successfully working apparatus, so that on its completion it would properly heat the building. There were to be two sectional boilers of a certain manufacture, which were to be complete, with all trimmings, castings, fire tools, etc. These boilers were to be connected with pipes of the proper size, and fittings to radiators and stacks of indirect radiation, throughout the different stories. All mechanical devices for making the apparatus operative for the purposes of heating and ventilation were to be furnished and applied, together with whatever should be necessary to constitute a first-class heating apparatus. These specifications and provisions of the contract are plain, and need no interpretation from the court. Then we come to the guaranty, which is made a vital feature of this controversy. The defendants guarantied that this apparatus would heat the building to a temperature of 70 degrees Fahrenheit, in any winter weather, with a consumption of not more than 175 tons of coal in each season of eight months, if the boilers were properly fired. This is This is a guaranty of the capacity of the apparatus; that is, that as it should be put up and established in the building by the defendants, it would heat the building to the specified degree of temperature in any winter weather; and this means the building as it was situated, and with its exposure, and according to its structural arrangement and design, as shown by the plans. It means, also, that if necessary it would heat the entire building to the specified degree of temperature, and that the consumption of coal should not exceed the specified amount per season. But the guaranty also means that the apparatus would do this work if it was properly managed. Of course, the defendants are not to be understood as warranting that the apparatus would meet the requirements named, under negligent or incompetent management; and here I instruct you that if this apparatus failed to heat the building, or any part of it, to the required degree of temperature, because of careless or unskillful or incompetent management on the part of any employe of the plaintiffs to whom its care and charge were intrusted, and if it would have met the requirements of the guaranty under proper care and competent management, the plaintiffs, and not the defendants, are answerable for such failure. The defendants, as I have said, are to be held to a faithful performance of their contract, and if in fact they did perform, by putting into the building a complete apparatus, capable, under proper care and competent management, of doing the v.21F,no.2-8

required work, then they ought not to be held accountable for any failure of the apparatus, resulting from negligence or unskillfulness or incompetency in its management by the plaintiff's employes. In this connection I give you the eighth instruction asked by defendants, as follows:

"In regard to the sufficiency of this steam-heating apparatus, the contract between the parties provides that the same must be adequate to heat the building to a temperature of 70 degrees Fahrenheit, in any winter weather, with a consumption of not more than 175 tons of coal, if the boilers are properly fired.' And if the jury find from the evidence that said boilers were not properly fired while the plaintiffs had charge of the heating, then the failure of the apparatus to conform in these particulars cannot be assigned as a breach of the contract."

I do not say or intimate what was the fact in relation to the firing of the boilers or the management of the apparatus; that is a question which it is your exclusive province to pass upon. As I have indicated, if this apparatus, as put into the building by the defendants, did not meet the requirements of the guaranty, the defendants cannot be relieved from their obligation by claiming that the building was so situated as to be peculiarly exposed to the winds of winter, or that it has an unusual extension of glass surface, for they contracted with reference to that state of facts. And in regard to workmanship and materials used in the construction of the building, externally and internally, for the purpose of protection against cold, I instruct you that the defendants contracted with reference to such quality of workmanship and materials as ordinarily enters into and as would ordinarily and naturally be expected to be placed in buildings of the class and character of this building. If first-class workmanship and materials are ordinarily put into such buildings, then the defendants had the right to expect that such workmanship and materials would be put into this building. The defendants did not contract against mechanical defects or deficiencies in construction which ought not to have existed, if any such did, in fact, exist. A good deal of testimony has been produced in relation to the construction of windows in the building. The defendants had the right to expect, when they made their guaranty, that the windows and window-frames and casings would be so constructed and adjusted as to afford such security against the external atmosphere as is ordinarily provided, and as it would be naturally expected the builders would provide in such a building. The defendants did not guaranty to protect the inmates of the building against exposure to cold arising from mechanical defects in the windows which ought not to have existed in such a structure, if any such defects did, in fact, exist. The meaning of their guaranty is that the apparatus would heat the building to a temperature of 70 degrees Fahrenheit, in any winter weather, with the windows constructed and adjusted as it would be ordinarily expected they would be constructed and adjusted in such a building. In other words, as is stated in one of the instructions asked by the defendants:

"If the jury find from the evidence that, as now claimed by the defendants, sufficient heat was produced and generated to heat the building to the required temperature, but that the same could not at all times be retained in some of the rooms on account of defects in the construction, not manifest from the original plans and specifications, and beyond the control of these defendants, then such occasional insufficient heating thus caused cannot be properly laid to their charge."

Whether there were such defects in the construction of the building as is claimed by the defendants, is a question of fact for you alone to determine; and whether, if there were defects, the alleged insufficient heating of the rooms, or any of them, was attributable to such defects, is also a question for your sole consideration.

As to rooms containing grates or fire-places and ventilating shafts, if the proposed arrangement and construction of the rooms were shown on the plans, then the defendants must be held to have contracted with such arrangement and construction in view. In this connection, with slight change, I give you the eleventh instruction asked by the defendants:

"If the jury find from the evidence that subsequent to the signing of the contract changes and alterations were made by order of the architects, either in the building or heating apparatus, that interfered materially with the carrying out of the original contract in heating said block, then such changes were at the risk of the owners; and for insufficiency of the apparatus in any particular, growing out of such alterations so made, the defendants would not be responsible."

As to the chimney in the building, about which testimony has been given, I have only to say to you that if the plans of the building showed what were to be the size, height, form, and capacity of the chimney, and the construction and arrangement of its flues, and the defendants could ascertain the same by inspection of the plans and drawings, and if, subsequently, there was no agreement to change the size and capacity of the chimney or flues, then they must be held to have made their contract with reference to such plans. If the plans were ambiguous in that particular, or did not specify details in the construction of the chimney, so as to enable the defendants to know what kind of chimney was to be constructed, then they had a right to suppose and expect that a sufficient and properly constructed chimney would be erected, with properly arranged flues, so as to permit the efficient operation of such a steam-heating apparatus as they proposed to put into the building. If, during the progress of the work, the defendants were advised of the proposed form and construction of the chimney, and requested certain changes to be made, and such changes were accordingly made, and they afterwards placed the apparatus in the building, then they cannot complain of such changes as tending to render the work of the apparatus inefficient. Further, in the language of one of the instructions asked, "if the jury find from the evidence that subsequent to the signing of the contract it was promised and agreed to enlarge the size of the chimney beyond

what the original plans showed it to be, and that such promise and agreement were not faithfully carried out, then, and in such case, occasional defects in the working of said steam-heating apparatus, caused by the failure to enlarge the size of the chimney, are not chargeable to the defendants in this case."

Now, gentlemen, I think I have said to you all that I am required to say in considering the plaintiffs' case concerning the rights, duties, and obligations of the parties under this contract. Counsel, in argument, have stated to you with clearness the points of difference between the parties and the respective claims they make. I shall not travel over the field of facts covered by the evidence. Upon the proofs so fully laid before you, you must determine whether the defendants failed to perform their contract as contended by the plaintiffs, or whether in fact they fulfilled its requirements, as they insist they did. [The court here stated to the jury the respective claims of the parties upon this branch of the case.]

In establishing their case, it is incumbent upon the plaintiffs to satisfy you by the evidence that the apparatus did not fulfill the requirements of the guaranty; and in determining this question you have a right to consider, among other things, whether a fair and sufficient test of the heating capacity of the apparatus was or was not made before the plaintiffs called on the defendants to remedy the alleged deficiencies therein. If, under proper management and proper firing of the boilers, the apparatus in question was inadequate to heat this building, constructed according to the plans and specifications, to a temperature of 70 degrees Fahrenheit, in any winter weather, with a consumption of 175 tons of coal in a season of eight months, and if such failure to so heat the building was not attributable to such defects or changes in the construction of the building, if any, as I have instructed you the defendants did not contract to provide against, and were not answerable for, then the plaintiffs are entitled to an allowance of damages in their favor. If, on the contrary, under competent management and proper firing of the boilers, the apparatus was adequate to heat the building constructed according to the plans and specifications, and in such a workmanlike manner as I have said to you the defendants had a right to expect it would be constructed, to the specified degree of temperature with the specified consumption of coal per season, then the plaintiffs are not entitled to recover damages against the defendants. So, too, if the apparatus had the necessary heating capacity to do the required work, but failed to heat the building to the extent required by the contract, and such failure was solely occasioned by incompetent management of the apparatus or firing of the boilers by the plaintiff's employes, or by such defects or changes, if any, in the construction of the building as I have said the plaintiffs were alone responsible for, or by either of those alleged causes, or all of them combined, then the plaintiffs are not entitled to recover.

If you find the plaintiffs entitled to recover, the next question is, what damages is it permissible to award them? Upon that subject I instruct you that the measure of the plaintiffs' damages, if the defendants have broken their contract, is the difference between the value of the apparatus in its alleged defective condition and what its value would have been if it had met the requirements of the contract. This latter sum-that is, the value of the apparatus if it had been such as the contract called for-may be more than the contract price or it may be less, but it is obviously the proper standard by which to measure the plaintiffs' damages, because such an apparatus was exactly what the plaintiffs were entitled to, and then the contractor obtains, also, just what his defective work is worth. White v. Brockway, 40 Mich. 209; 2 Suth. Dam. 482. So, gentlemen, if you come to this question in the case, you will determine from the evidence what was the value of this apparatus in its alleged defective condition; then, what would have been the value of the apparatus if it had fulfilled the conditions of the contract; and the difference between those values would be the plaintiffs' damages. Then, having thus ascertained the amount of such damages, you will allow to the defendants or give them credit for the amount still unpaid them on account of the apparatus, such amount being ascertained on the basis of the value of the apparatus. To illustrate, and you will understand what I now say as wholly illustration, and not as any intimation of any opinion of the court upon the facts of the case,suppose you find the contract broken; then suppose you find the value of such an apparatus as the contract called for to have been $15,000, and the value of the apparatus in its alleged defective condition to have been $8,400,-then the difference between these two sums, which is $6,600, would be the plaintiffs' damages. Then, deducting from the $6,600 what remains unpaid to the defendants, which is $5,900, the balance would be $700, and that would be the amount of the verdict in favor of the plaintiffs. Again, to illustrate, suppose you should find the value of such an apparatus as the contract called for to have been $10,000, and the value of the apparatus actually put into the building to have been $8,400, then the difference between those two sums, which is $1,600, would be the plaintiffs' damages. In such case you would apply this $1,600 on the $5,900 unpaid to the defendants, thereby reducing that sum to $4,300, and your verdict would then be for the defendants for $4,300. In other words, having ascertained the difference between the value of the apparatus actually furnished, and the value of the apparatus if it had done the work stipulated for in the contract, you will then allow the defendants what is unpaid to them, ascertained on the basis of the value of the apparatus they furnished, and then render a verdict either for the plaintiffs or defendants, as the final result of such an ascertainment may make necessary.

If you find that the defendants did not perform their contract,