MESSRS. EDITORS—According to your request, and to correct any false impressions which may have been suggested to your readers by the article in your valuable paper of the 13th inst., I will make a short statement relative to the application of David Bruce for an extension of his patent typecasting machine. He had not received, during the term for which his patent was originally granted, anything like a fair equivalent for his labor, time, and ingenuity in getting up the patent, such benefits having been realized by others than the inventor. Within the time prescribed by law, and according to the rules of the Patent Office, I drew up the necessary papers, which were duly filed and received at Washington. The [ Examiners reported favorably upon his application, and under the direction of the Commissioner, the necessary papers for the extension of his patent were prepared. These, by an oversight of a subordinate clerk, were put into the wrong "pigeon-hole," and were not found until a day or two after the expiration of tiie patent. This lapse of time only prevented the Commissioner of Patents from granting the extension of the patent. The inventor now, with the concurrence and approbation of the Commissioner, asks Congress to correct the mistake caused by the inadvertence and oversight of the clerk, and to carry out the original intention of the Commissioner, by granting him the extension. Mr. Bruce, with myself, concur with you as to the general principle of extending patents by Congress, but asks, in this case, special legislation to forward the ends of justice. ALVAII TRAVER. New York, February, 1858.