The defendants were clearly liable to the plaintiff in this action, if they were guilty of negligence in the construction of the bridge by the fall of which the plaintiff was injured. This liability rests on two grounds.

The first is, that there was evidence to show that the defendants, in making the contract for the woodwork of the bridge, stipulated that the lumber might be carried in teams on the different sections of the bridge as they were completed, and before the whole structure was finished, and that each span was as strong by itself as the whole bridge, when done, would be. This stipulation was equivalent to an agreement by the defendants with the contractors for the lumber and his servants that they would use due care in the construction of the bridge, so that each span would support in safety a team loaded with lumber.

The other ground is the more general one, that in the absence of any express stipulation there was an implied obligation or duty resting on the defendants that they would use due care in the construction of the iron work of the bridge, so that subcontractors under them and their servants employed on other parts of the work should not be exposed to risk of injury while engaged in the due course of their employment or service, by reason of any neglect or want of reasonable care on the part of the defendants in building that portion of the structure which was to be made and erected by them. The privity, so far as any is necessary to support the action, is found in the relation which subsisted between the parties at the time of the injury to the plaintiff growing out of the contract under which the work was done, and in the execution of which the plaintiff was injured. The object of this action is not to charge the defendants by reason of the fault or neglect of a third person or subcontractor, but for the omission of a duty or obligation which rested on the defendants themselves. A person in entering into *121a contract takes on himself the usual and ordinary risks of the business in which he is thereby employed, including the negligence and carelessness of other persons who may be engaged in the same service or employment. For injuries which arise from such causes an employer cannot be held responsible in damages. But the law‘does not relieve him from all responsibility to those with whom he contracts. He is bound to use due care in the selection of those whom he employs to work in company with others, and to be reasonably diligent and cautious in obtaining proper materials, in the erection of adequate structures and in the procurement of suitable tools, machinery and other instrumentalities upon or by means of which an employment is to be carried on. Witte v. Hague, 2 Dow. & Ry. 33. Randleson v. Murray, 8 Ad. & El. 109. Collett v. London & North Western Railroad, 16 Q. B. 984. Snow v. Housatonic Railroad, 8 Allen, 441, and cases cited.

These principles were substantially recognized and adopted by the court at the trial. If the instructions on this part of the case are open to any criticism, it is that they are wanting in fulness; or rather, they are too abstract, and do not sufficiently meet the several aspects of the case on the evidence, as presented by the specific prayers for rulings submitted in behalf of the defendants. We are not prepared to say, however, that the defect or omission in the instructions affords sufficient ground for a new trial; nor is it necessary for us to determine this question, inasmuch as we are clearly of opinion that upon another ground the case must be tried anew, when an opportunity will be given for a fuller exposition of the rights and obligations of the parties growing out" of their relations towards each other than was given on the former trial.

We think a substantial error was committed in the failure to give adequate instructions on the issue raised by the averment in the answer, that the plaintiff had settled for and received compensation from the defendants for the injuries which form the subject matter of the present action. The receipt signed by the plaintiff, in conn action with other evidence of a settlement adduced at the trial, was prima facie sufficient to establish this *122ground of defence; and it was incumbent on the plaintiff to rebut it by proof of some mistake or fraud. On this issue the defendants were entitled to insist that explicit instructions should be given to the jury ; and these were asked for by their counsel. The jury should* have been told that the presumption was that the plaintiff knew the contents of the paper which he signed, and that an acknowledgment in writing by him that he had received payment in full for the damages resulting from the accident was a complete defence to the action, unless he could show that he was deceived or mistaken in making the settlement and signing the receipt. The only instruction given on this point was, that if the parties “ fairly settled the claim ” it would be sufficient to bar the action. This was altogether too vague and uncertain to guide the jury in passing on the issue presented for their decision. It did not define what would constitute in legal effect a fair settlement. It left it for the jury to suppose that if, on the whole, they were of the opinion that the compensation which the plaintiff agreed to receive in satisfaction was inadequate or insufficient to indemnify him, they were at liberty to disregard the settlement, set aside the receipt, and render a verdict in bis favor for additional damages. Nor did the remark of the court that “ the amount received by the plaintiff in the settlement was immaterial to its validity ” cure the defect. It left the door still open for the jury to disregard and set aside the settlement, although it was made without any fraud or deceit on the part of the defendants, or any mistake or misconception by the plaintiff. For this reason the order must be

Exceptions sustained.