Gunpowder mixed with powdered glass, and struck with a hammer is said to explode. An advertisement appeared in the public papers some time in 1813 or 14, signed T. Ewel, addressed to powder manufacturers, by which it appears, in the words of the advertisement, that "he obtained from the United States a patent right for three very simple and important improvements in the manufacture of gunpowder, which do most truly diminish more than one half the risk, the waste, and the expense of the manufacture. They consist in boiling the ingredients by steam, in incorporating them without the objection of barrels, the danger of pounders, or the tediousness of stones running on the edge: and in the granulation effected by a simple machine turning by hand or water, and graining more in a day than twenty hands, losing not a particle of dust, and making not half the quantity for re-manufacture. The advantages of this mode have been so great that he had to discharge half his workmen from his manufactory, as will be readily accounted for by those accustomed to the tediousness and loss from graining, particularly the press powder by the sifter and rollers, &c." We have not seen the plan in operation, and, therefore, can say nothing respecting it; but it would appear, from the description, that the process was conducted altogether by steam. It is true, that the use of steam is no new application, nor was it then, as it had been used in Europe for heating of dye kettles, in soap boiling, distilling, for warming apartments, and many other purposes. The application to that particular use, that of the manufacture of gunpowder, may be original as far as we know, notwithstanding steam has been applied by means of pipes, &c. as is used at present in some manufactories, for the drying of gunpowder. Professor, now president Cooper, of Columbia College, S. C. (_Emporium of Arts and Sciences_ vol. ii, p. 317) in making some observations respecting that publication, believes, that the application of steam to the manufacture of gunpowder to be practicable, and in reference to the advertisement, also a real improvement; and speaking of steam for that purpose adds, "whether it be adopted in England or not, or whether among the numerous patents granted for the application of steam to the arts and manufactures of that country, I know not."