kelIjS V. m'kenzib. 2S7 �cess of treating bark-tanned lamb and sheep skin by means of a compound in which heated fat liquor waa an essential ingredient. This patent was surrendered and reissued for the use of fat liquor in any condition, hot or cold, in the treatment of leather, and for the process of treating bark-tanned lamb or sheep skin by means of a compound in which fat liquor was the principal ingredient. The state of the liquor was not mentioned as essential to the treatment or accomplishment of any of the results sought. It was only stated as a thing to be desired that the liquor should be heated, and that it would be preferable that other ingredients were mixed with the heated iiquor tp make the compound mentioned. The court held the reissue void, upon the ground that the use of the liquor hot or cold was an expansion of the original patent, which required it to be hot. And this, although the patentee was the first to discover that fat liquor, in any condition, could be used for the purpose specified. It was said — ■ �" That as a reissue could only be granted for the same invention einbraced by the original patent, the specification could not be substantially changed, either by the addition of new matter or the omission of important particulars, so as to enlarge the scope of the invention as originally claimed. The origina patent was not inoperative nor invalid from any defective or insufflcient speci- fication. The description given of the process claimed was, as stated by the patentee, full, clear, and exact, and the claim covered the specification; the one corresponded with the other. The change made in the old specification, by eliminating the necessity of using the fat liquor in a heated condition, and making in the new specification its use in that condition a mere matter of convenience, and the insertion of an independent claim for the use of fat liquor in the treatment of leather generally, operated to enlarge the character and scope of the invention." �So, in Powder Company v. Powder Works, 98 U. S. 126, it was held that letters granted for a certain process of exploding nitro-glycerine would not support reissued letters for a composition of nitro-glycerine and gunpowder and other substances, even though the original appli- cation claimed the invention of the process and the compound. In this case Mr. Justice Bradley says : �" The specification may be amended so as to make it more clear and distinct, the claim may be modifled so as to make it more conformable to the exact rights of the patentee, but the invention must be the same. So particular is the law on this subject that it is declared that no new matter shall be introduced into the specification. This prohibition is general, relating to all patents, and by ' new matter ' we suppose to be meant new substantive matter, such as would have the effect of changing the invention, or of introducing what might be the subject of another application for a patent. The danger to be provided against was the temptation to amend the patent so as to cover im- ��� �
