[26] A method of rendering changeable the sound of the same pipes in the organ, which had occurred to the writer, but which was not inserted above on account of the supposed difficulty of making the change sufficient in degree, he has since found to have been executed by the Rev. H. Liston, who has succeeded, by means of shaders capable of being brought before the mouths of his pipes by the action of pedals, in giving them three distinct sounds each, varying by two commas. (See the description of his Enharmonic organ, in Rees' Cyc. or Tilloch's Phil. Mag.) His scale embraces 59 intervals to the octave, and is intended to produce perfect harmony in all the keys. But as it will require the use of pedals perpetually, even on the same key, and a ready and perfect knowledge of small musical intervals, which practical musicians can seldom possess, there is no probability that it will ever be extensively adopted. Perhaps, however, four or five sounds, such as D♯, E♯, A♭, D♭, might be added to the common scale of 12 intervals by means of his mechanism, with advantage. An instrument thus furnished would require the use of pedals but seldom, and would contain chromatic degrees sufficient for the accurate performance of the great mass of organ music. [27] These picture, as is well known, represent the assault on Quebec, and the battle of Bunker's Hill. CONTENTS. GEOLOGY, MINERALOGY, TOPOGRAPHY, &C. Page Art. I. Hints on some of the Outlines of Geological Arrangement, with particular Reference to the System of Werner, in a letter to the Editor, from William Maclure, Esq. dated Paris, 22d August, 1818 209 Art. II. On the Geology, Mineralogy, Scenery, and Curiosities of Parts of Virginia, Tennessee, and the Alabama and Mississippi Territories, &c. with Miscellaneous Remarks, in a letter to the Editor. By the Rev. Elias Cornelius 214 Art. III. Notice of the Scenery, Geology, Mineralogy, Botany, &c. of Belmont County, Ohio, by Caleb Atwater, Esq. of Circleville 226 Art. IV. Remarks on the Structure of the Calton Hill, near Edinburgh, Scotland; and on the Aqueous Origin of Wacke; by J. W. Webster, M.D. of Boston 230 Art. V. Localities of Minerals 236 1. Localities by the Rev. F. C. Schaeffer _ibid._ 2. Minerals of Guadaloupe and Porto Rico 237 3. Molybdena in Shutesbury, Mass. 238 ---- Pettipaug, Con. 242 4. Rose Quartz in Southbury, Con. 238 Limpid Quartz in West Canada Creek, N. Y. 241 5. Plumbago in Cornwall, Con. 239 6. Coal at Zanesville, Ohio _ibid._