The opinion of the Court was delivered by
— The numerous errors that have been assigned, have in the argument been classed under three heads, and may , be so considered. The plaintiff alleges that the consideration of the original note could not be inquired into, but the party was concluded by having given another note, and therefore the evi
5th, 6th, and 8th errors. These errors regard a material question in the cause. The claim of Sharp, from whom the plaintiff purchased, was “ for the tappit-arm, as above described, with its appendages and arrangements.” It seems to be admitted that the description contained in the specification is sufficiently precise and perspicuous; but the court below held that the patent was void, because the claim is to the entire arm, which Sharp was not the inventor of. The law on the subject of patents often goes upon nice grounds, and in many instances the nature of the subject compels this. Care, however, ought to be taken by a court not to involve patentees in too great difficulties in construing their claims, and to sustain them by a favourable construction, if they can. Though Sharp was not the inventor of the forge-hammer arm, but it had been long in use before, yet if his invention is of a mode of making that arm in a different manner from any ever before made, and it thereby produces a new and useful result by a new combination of old materials, then he could not well claim it in a better manner than as a new arm. When there is an addition to an old machine or part of an old machine, or a mere alteration of some of its subordinate parts, the claim may be for an improvement only; but where the whole mode of forming the thing, and its effect, are new, it may be claimed as new. Thus it appears here by the evidence, that previously there had been wooden arms barrelled/with iron, and iron arms barrelled with wood; but these will not correspond with Sharp’s specifica
As to the remaining point, the failure of consideration, that seems to go on the ground that it would be against equity to compel payment for a patent right when it turns out that no patent right existed. Chancery would relieve against such demand on the ground of material error or misconception going to the essence of the contract, although there was no fraud in the vendor. As, where one sells a messuage to another which was at the time swept away by a flood, or destroyed by an earthquake, without any knowledge of the fact by either party. There a Court of Equity would relieve the purchaser, upon the principle that both parties intended the purchase and sale of a subsisting thing, and implied its existence as the basis of their contract. Hitchcock v. Geddings, (4 Price 135, 141); 2 Kent’s Com. 469; 1 Story’s Equity 157. In this state the subject is fully discussed in the opinion of the court in Bellas v. Hays, (5 Serg. & Rawle 427), and the validity of such a defence established. See also 9 Serg. Rawle 80; Pom. on Cont. 122: 3 Watts 32.
Judgment reversed, and venire facias de novo awarded.