After the foregoing statement of the case,

delivered the opinion of the Court, as follows:

Without going into the prior art, in full, it is enough to say that the Brown patent shows, in an automatic fire-extinguisher, a valve and separable valve support, combined with separable clamping plates, fusibly connected. Freeman was not the first to introduce into the art the conception of a strut which, though composed of different members was, as an entirety, separate from the environing framework. The claim, on the score of separableness of the strut, can not, therefore, be sustained.

But it was insisted at argument that neither the Brown device, nor any of the preceding fire extinguishers, show a strut, the members of which are set angularly to each other, and pivoted one upon the other. In the Brown device the convex end of one member of the strut fits into the concave shoulder of the other, and the drawings show that the pivoting is not out of alignment with the strut.

One of the chief difficulties of appellant’s case is that its existence is not, strictly speaking, along the lines of the patent under which it claims; nor do the claims lay any emphasis upon the idea of angular pivoting. We may go to the description to amplify a claim, but we can not, out of the mere descriptive portion of the patent, wholly create a claim. Whether the feature of angularity, upon which so much stress is now laid, would have been sustained, had it appeared in the claim, need not be now considered. It is sufficient that, as a matter of fact, no grant, upon that score, was either asked or allowed.

*538We are of the opinion, also, that the action of the Patent Office,, and Freeman’s acquiescence therein, upon the original application constitute a limitation upon the Freeman claims. In view of the prior art, including the Granger patent, we can see no occasion for adding the words, “to hold the parts of the valve supports in contact” unless it was meant that the contact should be by a direct clamping, as shown in the drawings; for the Granger patent brings about an operative contact by clamping at some distance off; and it was to avoid this citation that the additional words were introduced. We can not escape the conclusion that a limitation such as this was intended; at least, that it was so understood by the Patent Office; and this interpretation excludes the appellees’ device from the charge of infringement. .

The truth seems to be that present operative fire extinguishers— both those constructed by the appellant, and those constructed by the appellees — are, in the means leading to delicacy of adjustment, somewhat different from all the patents brought to our attention; and, if this difference be a step forward, it would be inequitable, by any strained construction, to bring this advance^ in the practical art within the monopoly of any of the patents that lag after.

The decree of the Circuit Court is, accordingly, affirmed.