In the case of Ambler v. Eppinger, 1890, the U.S. Supreme Court dealt with a dispute over a patent for an improvement in sewing machines. The plaintiff, Ambler, claimed that Eppinger had infringed on his patented invention by manufacturing and selling similar devices without his permission. However, the defendant argued that Ambler's patent was invalid because it lacked novelty as required under patent law - essentially claiming that this "improvement" was already known or used before he filed for a patent. The court ruled in favor of Eppinger stating that there wasn't enough evidence to prove any significant difference between Ambler’s device and previous inventions; thus failing to meet the requirement of novelty necessary for obtaining a valid patent right. Therefore, no infringement could have occurred since there was no valid exclusive right held by Ambler over such an invention.

The dissenting opinion in the case of Ambler v. Eppinger, 1890, argued that the majority's decision was incorrect because it failed to properly consider and apply principles of equity. The dissent held that there was a clear agreement between both parties involved in this dispute over property rights and therefore, the defendant should be bound by his contract with the plaintiff. It also contended that even if there were some ambiguity or uncertainty regarding certain terms within their agreement, these issues could have been resolved through further interpretation or construction rather than outright dismissal of the contract as invalid. Furthermore, it disagreed with how much weight was given to evidence presented by one party without sufficient counter-evidence from another party being taken into account appropriately during trial proceedings.