(3) As to Infringement. - Here the second part of the judgment of Wills J. comes into play, and we have to examine the alleged infringement by the side of the "standard" already ascertained from the specification. Clearly, there is no upward tongue, and, as that is "an essential step," the appellants have not infringed. The case is thus clearly within the latter part of the quotation from the judgment of Fletcher Moulton L.J. in the Vidal Dyes Syndicate Case[8]. We should add that the contention that in fact there was an upward tendency given to the flange in the alleged infringements, equivalent to an upward tongue, is not sustained. Inspection discloses nothing appreciable of that nature, and, as inward flanges were old in 1900, it is a proper deduction from Mr. Fry's evidence, if evidence indeed were necessary, that as long as such flanges were made, exactitude of angle could never be attained with certainty. Of course, if it were seen that advantage was being taken to manufacture a real bend so as to be in effect and substance an equivalent for the upward tongue, including in one curved piece the substantial equivalent of the flange combined with the tongue, nothing in this decision would protect it. The tribunal - Judge or jury - would be ready to detect an act of that nature, and prevent it. But that has not so far occurred. Something was said about the purpose for which the ploughshares were intended, namely, to be used by purchasers from the appellants as fittings to their patent footpiece. Assuming, but certainly without deciding, that the mere use of the share upon the footpiece would constitute an infringement, it is clear that the sale of an article, not in itself an infringement, does not constitute an infringement, even if sold with the knowledge that the purchaser intends to use it for the purpose of infringement (Dunlop Pneumatic Tyre Co. Ltd. v. David Moseley & Sons Ltd.[9]). We are strongly persuaded that failure to bear this point in mind has led to much of the misconception in the present case, because all that has been said about the purpose of the share, and the object of using it in combination with the rib of the respondents' footpiece, appears to be referable to the idea negatived by the case mentioned.