The first question reserved for our advice in this case must be answered in the negative. The evidence was not admissible.
It is not material to enquire whether or not generally, on the sale of a patent right, there is an implied warranty of its validity. There is undoubtedly a strong current of authority in that direction. And the cases in this country where in actions for the price of a patent right or patented' machine the defendant has prevailed on the ground of a failure of consideration, are quite numerous. Where there was an express warranty, or the vendor by representation expressly professed to sell the patent as a valid one, and the purchaser relied on that profession, or where the vendor knew that there was a defect in the patent and that it was invalid and concealed the fact, (although he made no express representation whatever,) and in such concealment was guilty of fraud, the correctness of the decisions cannot be questioned. And one or another of these elements existed in a majority of the cases collected by Mr. Law in his Digest, many of which have been cited on this trial. But it is questionable whether as between two assignees of a patent right, neither of whom has any opportunity to know whether it is invalid for want of *443novelty or not, especially since tlie reorganization of tlie Patent Office and a provision for a determination of that question by examiners before the patent is granted, and a series of federal decisions holding such a patent prima facie evidence of novelty, the vendor who acts in good faith, in the absence of fraud, express warranty, or any representation or fact other than the mere fact of sale indicating that he sold the patent as valid, the vendor should be holden to an implied warranty and failure of consideration on that ground, if in fact invalid, or the vendor be permitted to defend upon the ground of a mutual misconception of a fact. The English courts would not now so hold on either ground; and I am inclined to think that, upon principle, a discrimination should be made here.
But however that may be where, as in this case, there is not only an absence of fraud, express warranty or representation as to the validity, and of any fact or circumstance indicating that the vendor professed to sell a valid patent, or that the parties mutually misconceived, but clear evidence on the face of the instrument that the parties mutually contemplated the possibility if not the probability that the patent was invalid, and provided by the form of the instrument and its stipulations for the contingency, it is very clear that there is no ground on which the.vendee can be permitted to set up a failure of consideration. The instrument, according to what seems its clear import and meaning, binds the vendee to pay so long as he is not judicially disturbed in the enjoyment of the patent, and releases him from the obligation' when in fact thus disturbed. It is not pretended that he has been so disturbed ; and if he has in fact enjoyed, he must pay, and cannot be permitted to set up by way of defence a defect, if there be one, in the patent. ■
The opinion thus expressed renders the second question wholly immaterial.
The remaining three questions involve a construction of the specification and will be considered together.
The court find that the way and process used by the defendants is the same way and process secured by the patent, unless *444the patent- is to be so construed as to necessarily require the use of a size of the particular composition described in Heck’s patent; or is to be so construed as to necessarily exclude any and every means of drying the thread except by friction of the brushes; or is to be so construed as to necessarily require the use of a series of independent cylindrical revolving brushes.
The rules of construction in relation to specifications adopted by the federal courts are peculiar but are generally followed. Construing the specification by those rules, we are satisfied that it does not call necessarily for a size of the particular composition described by Heck. He describes the saponaria root, salep root and soap as the “most important” of his size, but not as essential ingredients. They are also to be used in connection with other mucilaginous ingredients. He says therefore that his size contains those articles, and that they are the most important; but he disclaims the composition as such, and claims merely the saturation of the thread with a size substantially such as described. Construing the parts of the specification together therefore, and adopting the rule that it is to be so construed as to sustain it if possible, we are of opinion that it does not necessarily require the particular size described; but that any mucilaginous size containing ingredients of equivalent effect with saponaria, salep and soap is a use of that part of the process.
And we are also of the opinion, (adopting the same rule of construction,) that the defendants use a machine of equivalent effect with that of Heck. The object of Heck’s arrangement of brushes was to polish, soften and dry the thread. This was to be done by revolving brushes. The defendants claim that although they use a revolving brush, and thereby polish and soften the thread, yet that they do not use a series of brushes for the purpose of drying it. They do use however a material part, and the most material part of Heck’s process. They brush by a revolving brush, in connection with the use of a size for the purpose of polishing and softening the thread. They use a part of Heck’s process'therefore, and the most material part; and the fact that they dry by an *445additional and different device does not justify them in the use of the revolving brush to polish and soften. A difference in use which is merely a difference in extent, is not a different use ; and under the finding of the court we think it very clear that the defendants are liable, and the superior court must be advised to take the account and decree accordingly.
In this opinion the other judges concurred.