UNITED STATES SUPREME COURT DECISIONS ON-LINE

When, under a contract to furnish and to put in complete operation in the purchaser's mill machinery of a certain description and quality for a price payable partly upon the arrival of the machinery at the mill and partly after the completion of the work, the machinery furnished and set up does not, when tested, comply with the requirements of the contract, the purchaser, upon giving notice to the seller that, if the latter does not "put the mill in repair so that it will do good work," the former will do so, is entitled to deduct, in an action for the unpaid part of the price, the reasonable cost of altering the construction and setting of the machinery so as to conform to the contract.

Whether a witness called to testify to any matter of opinion has such qualifications and knowledge as to make his testimony admissible is a preliminary question for the judge presiding at the trial, and his decision of it is conclusive unless clearly shown to be erroneous in matter of law. clubjuris

Page 130 U. S. 521