(dissenting).
To the above dissenting opinion, with which I join, I wish to add the following comments. Even assuming arguendo that the counts are ambiguous so that it is necessary to look outside the counts in issue for an interpretation of their scope, important consideration should, in my view, be given to those claims of Mc-Cutchen other than those copied by *624Oliver.1 The McCutchen patent contains ten claims, six claims of which, including the two making up the interference counts, are absolutely silent as to exposed reference surfaces. The four remaining claims all end with the following language:
* * * the lapped surfaces on said first member projecting substantially beyond the respective ends of the second frame member and defining broad exposed reference faces thereat.
This glaring variation in the scope of the patent claims indicates one thing to me, that the patentees sought coverage on a structure which did not require exposed reference surfaces as well as on one that did. At the risk of deciding this case in the “rarified atmosphere” of claim semantics rather than on a “down to earth” basis, it seems to me that where an applicant of his own volition seeks broad patent coverage during prosecution, he should not be permitted at a later date to shrink such coverage in order to avoid a contest of priority on an invention so broadly defined.
I cannot agree with the approach which is to deprecate claim language as mere semantics, and elevate the disclosure to gospel. Such an approach fails to consider the dynamics of patent prosecution. The specification, being written prior to any action by the Patent Office, often emphasizes matter which later proves to be minor or completely lacking in novelty, whereas other matter proves to be of utmost significance to patent-ability of the invention. The claims on the other hand are subject to amendment in order to meet the strictures of 35 U.S.C. § 112 — “particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.”
It is the patent practitioner’s duty to define his client’s invention in the claims. This may be, and usually is, done by drawing claims of varying scope. Significant evidence, if not the best evidence, of the scope of any one claim is the language employed in other claims. Certainly, the express limitation to “broad exposed reference faces * * * ” in those of McCutchen’s claims not in issue here is strong evidence that the other claims, forming the counts in issue, do not by implication contain such a limitation. The majority completely disregards this evidence, whereas I view it to be determinative.
I would affirm.
. According to Rivise and Caesar, § 56 (1940), it is a fundamental rule of count interpretation that
It is proper to compare a count with the other claims of the interfering cases in order to find support for a particular interpretation of the count.
See also Rivise and Caesar, § 67 (1940) which fully considers this rule and cites as authority therefor several cases of this court.