'îTS TEDERAIi EBPORTEB. �quires, the burden is shifted on to the plaintiff to show invention or discovery by the patentee still prior to that. �The evidence on which the plaintiff claims to make this out is weak; not so much in the number and charaoter of the wit- nesses, as in what they pretend and appear to know that Eagleton discovered and did, They fail to set forth such experiments and tests, and resulta examined by him, as would ordinarily accompany such a discovery. On this subject bis original application is very weighty and important. As said by Mr. Justice Nelson in Manny v. Jagger, 1 Blatchf. 372 : " The description of the invention by the patentee, in his own language, affords the highest evidence of the thing or instru- ment which he claims to bave discovered." �In view of ail the evidence on this subject, it not only does not appear that Eagleton did make this invention or discov- ery before the others, but it appears that he did not, and that probably it never came to his knowledge while he lived. �It is said in argument that it is not necessary he should bave known the full effect of the process he invented in order to uphold the patent, and that if he invented japanning it might not be necessary for him to know that japanning would temper. It is doubtless true that an inventor need not know ail the uses to which his invention is capable of being put; and equally true that there must be some patentable invention patented before any use of it can be covered by the patent. Here, japanning by itself was not patentable, Eagleton described no mode of japanning which would temper or strengthen the steel. The temper and strength are produced by the beat altogether, and not at ail by the japan, He did not even mention that "the japan was to be applied with beat, Had a patent been granted to him on his application it would have covered japanned springs, not tempered springs. He did not invent or discover anything patentable of which any one use eould be made, and, a fortiori, not anything of which more tban one use could be made. �Upon this view of these questions of fact, the issue of fact joined upon the traverse of the answer must be found for the defendants. ����
