Samuel Blatchford

“ But the material point is the extension of the invention claimed, by the addition of claim 1 of the reissue, the words in which, 'substantially as set forth,' refer to the new matter in the reissue, that the in the original specification which indicates cooled with water, in such a manner that the tymp, or forehearth, and the wall stone can be dispensed with.' The intention manifestly was to construe the first claim so as to cover any kind of blast furnace with a closed breast, having a slagdischarge opening, cooled in any manner or to any extent by water. ”

“ It is apparent, from the description contained in the specification of the original patent, that Lurmann considered his invention to consist essentially of a removable slagdischarge piece, cast with numerous channels or pipes running through it, formed with a dovetail at its upper end, fitted into the bottom of a stationary metallic plate connected with the furnace, and provided with channels or pipes, so that water might flow through the slag-discharge piece and plate, conjointly or separately, that they might be cooled while the furnace was in operation. ”

“ This testimony shows that, instead of desiring merely to remedy formal defects which appeared on the face of the papers, Asmus waited until experience and reasoning had shown him the broadest formula in which to express the claims of his patent, so as to cover all possible modifications. ”