MESSRS. EDITORS.—Will you be 80 kind as to inform an unfortunate inventor if there is any redress for him when another party has sworn to his invention, and secured Letters Patent for it 7 My case is this : I am employed in a manufacturing concern, and have made several improvements in my own time, which the company claim as their own, simply because I am in their employ. Is this right ? Yours truly, H. H. C. Albany, N. Y., June, 1858. [Our correspondent asks two questions, and we have given them publicity because there are, no doubt, others interested in this subject. He inquires if there is any method whereby he can obtain redress from a party who has appropriated his invention, made oath to it, and secured a patent, which he asserts has been done in his case. His charge is a serious one, but there is a method of obtaining redress, and he can, without much expense, avail himself of its requirements. He must apply for a patent for his invention in the mode prescribed for this purpose, and of course it will be rejected on account of the prior patent of the other party. He must then request the Commi.sioner of Patents to declare " an interference," which act will laad to the taking of testimony, and if he proves himself to be the original inventor, a patent will be issued to him. If the opposing party still refuses to yield, the United States Circuit Court will, upon a proper hearing, grant an injunction against the infringing party. Should this question be tested by a trial at law, if he establishes his claim as the originHl inventor, the court can then declare the patent issued to be null and void. If our correspon. dent cannot prove that he is the original inventor of the improvement, he has no redress ; he must bear his lot, and consider himself to blame for his ignorance of the patent law, or of neglect for not availing himself, in due season, of its benefits. In the course of our experience the question is often asked, " can an employer claim the inventions of a workman in his service 7" We answer emphatically NO, unless there is a specific understanding between them that the innntion is "got up" for the exclusive benefit of the former. We are fully sensible that there are some employers who regard their claims as complete to any improvement, valuable or otherwise, when made by a workman in their employ. Such an assumption, in the absence of any agreement, has neither the support of law nor equity. This principle does not apply to a machine made for the employer upon any improved plHn. The employer can use the specific machine, but if the patent is issued he cannot sell to others the same right.—EDS.