Nitro-Glycerin Patents and Litigation. It is seldom that any valuable invention has been brought into public use without costly litigation being entailed on the inventor; and especially is this the case in chemical discoveries, either by pretenders who would interfere with the inventor who has turned his discovery to practical account, on the plea of having previously conceived the same idea, or by unscrupulous individuals who would appropriate to their own use, without payment, the fruits of the labors of other men’s brains; hence the writer did not altogether escape, as will be seen by the following remarks on the subject. [Illustration: Miners ascending Central Shaft.] I will commence by stating briefly that a patent was granted and four re-issues of the same made to Alfred Nobel and his assignees, for the use of Nitro-Glycerin for blasting purposes, when “confined,“ and for a process of manufacturing the same, by running the glycerin and mixed acids together rapidly, in suitable proportions, into a tank of water. Now, it has never been denied that Sobrero was the discoverer of Nitro-Glycerin, and that it was competent for any one to manufacture that article. The only point, therefore, on which a patent could be obtained was for some improved method of making it. Accordingly, in the course of experiments, I discovered that by passing a current of cold, compressed air through the mixing glycerin and acids, a very valuable improvement was effected, economizing time and material, and rendering the process of manufacturing safer; and for this I obtained a patent on April 7, 1868. That my readers may see how far I was correct in my estimate of the patentable value of my invention, I give below the opinion of eminent counsel: NEW YORK, July 10, 1869. GEO. M. MOWBRAY, ESQ.: Dear Sir:—Pursuant to your request, I have examined your Letters Patent of the United States for inventions in the manufacture of Nitro-Glycerin, dated the 7th April, 1868. I recollect of aiding you in preparing the application for that patent, and of examining it immediately after it was issued. I believed then that that patent was good and valid, and nothing since has occurred that has changed my opinion or shaken my confidence concerning its validity. I have recently examined copies of the five re-issued patents to assignees of Alfred Nobel, and I find nothing in them, or any of them, which impairs the validity of your patent.