William R. Day,
Cimiotti Unhairing Company v. American Fur Refining Company…
“ In determining the construction to be given to the claim in suit, which is alleged to be infringed, it is necessary to have in mind the nature of this patent, its character as a pioneer invention or otherwise, and the state of the art at the time when the invention was made. It is well settled that a greater degree of liberality and a wider range of equivalents are permitted where the patent is of a pioneer character than when the invention is simply an improvement, may be the last and successful step, in the art theretofore partially developed by other inventors in the same field. ”
