6e2 fEDEBAL BEFOBTEB. �weîght, except as it is confirmed by others. I think, upon the evidence, I ought to lay out of the case the alleged use in Philadelphia and Hartford. �Moore returned to Windsor in the autumn of 1861, and four witnesses are called to prove that he used, and lent to others for use, a wrench like that of the patent, before October 1,1862. It is very diffioult for witnesses to fix within a month or even a year the exact time of an occurrence of no impor^ tance to themselves, to which their attention is called after the lapse of 16 or 17 years. This difficulty, inherent in the subject, must be fully overcome by one who assails a patent. Another question which always arises is whether the use was within the limita of a justifiable test or experiment. I have read the evidence with great care, and am satisfied that Moore did not make a wrench for sale until within two yeara before his application. As the value of his invention was not for his Personal use, as is often the fact with manufacturers who improve a machine used in their partieular business, so much as for the sale of the tools or the royalties, I consider this fact very important. The chief witness to prior use, E. F. Spaulding, gives a deposition which is clear and candid; but he had told one of the plaintifs, a very short time before he testified, that he had no means of fixing the date, and could not fix it. This he very fairly admits, and he does not explain how his memory has been refreshed. Besides, the evidence of this witness, while it is not wholly consistent with itself upon the other point, yet leaves upon the mind an impression that the use which he testifies to was experimental. Such is the fair resuit of his evidence at pages 235 to 237 of the record. And so of the only other witness whose means of knowledge were considerable, Edminster. The point which the defendant takes as to the use by Edminster is that Moore permitted him to try the wrench in order to induce him or his father to take an interest in it, and help Moore in procuring a patent. The witness so puts it. But I consider it too nice a point to say that the future patentee, when he permits a person to test his tool by a short use with a view to interest him in its being patented, is not testing his tool, but only the ����
