The opinion of the Court was delivered by
Sergeant, J.— 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*269denee offered ought to have been rejected. If, however, the consideration of the note for $565 now sued on, was nothing else than the former note of $800, and the former note was void for want of consideration, this was the only mode in which the defendant could show that the present note was without consideration. It is possible there might be circumstances under which the giving a new note would preclude the party; but these would properly come in in reply to the defendant’s proof, and not as an objection to the evidence. We think there was no error in this. The court seems, in the breaking of the cause, to have been misled' in admitting evidence in relation to the reverberatory furnace. • The slight evidence which had been previously given, when critically examined, contains nothing to show that the patent for the reverberatory furnace constituted any part of the consideration of the $800 note. Wolf, the witness relied on, merely says, he wrote the assignments and saw a note drawn up at the time, but could not say whether it was for the right, or whether it was signed. The deeds were separate, and so were the considerations — that • for the reverberatory furnace being $400, and that for the forge-hammer arm $800, the amount of the note in suit. It would rather seem that the note on which this suit was brought,, was given’ for the forge-hammer arm patent alone. The evidence ought therefore to have been rejected.
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*270tion. It is composed of wood and iron, each forming a substantial part of the arm; neither being properly an addition to or covering of the other, but constituting one whole, of which these materials are the component parts; and forming an arm, according to the testimony of Worrall and Shay, more elastic, durable and secure than former ones. Whether this invention was new and useful, was a different question; but there was evidence to show it was an arm formed differently from others and producing a new result. If so, it seems difficult to say how he could describe the old arm and his invention as an improvement of it. It could not properly be called an iron arm, because the wood is a material portion of it; nor could it be called a wooden arm. It is an arm composed of both, forming together a new element of power; at least this is what he claims, and has given some evidence to support. It seems to fall within those cases in which it has been held that old materials which produce a new effect may be the subject of a patent, on account of the novelty in the combination. 4 B. ¿y Aid. 541; 6 Moore 71; Dav. Pat. Cases 265; 2 JV. Hamp. R. 61; 1 Pet. U. S. Rep. 322; 3 Mer. 629; 8 TaUnt. 391. We are of opinion that these errors are supported.
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.