On the Boracic Acid. --Its Decomposition by Sir H. Davy. --Its Basis Boracium. --Its Recomposition. --Its Uses in the Arts. --Borax or Borat of Soda. --Of the Fluoric Acid. --Obtained from Fluor; corrodes Siliceous Earth; its supposed Composition. --Fluorine; its supposed Basis. --Of the Muriatic Acid. --Obtained from Muriats. --Its gaseous Form. --Is absorbable by Water. --Its Decomposition. --Is susceptible of a stronger Degree of Oxygenation. --Oxygenated Muriatic Acid. --Its gaseous Form and other Properties. --Combustion of Bodies in this Gas. --It dissolves Gold. --Composition of Aqua Regia. --Oxygenated Muriatic Acid destroys all Colours. --Sir H. Davy’s Theory of the Nature of Muriatic and Oxymuriatic Acid. --Chlorine. --Used for Bleaching and for Fumigations. --Its offensive Smell, &c. --Muriats. --Muriat of Soda, or common Salt. --Muriat of Ammonia. --Oxygenated Muriat of Potash. --Detonates with Sulphur, Phosphorus, &c. --Experiment of burning Phosphorus under Water by means of this Salt and of Sulphuric Acid. CONVERSATION XX. ON THE NATURE AND COMPOSITION OF VEGETABLES. 162 Of organised Bodies. --Of the Functions of Vegetables. --Of the Elements of Vegetables. --Of the Materials of Vegetables. --Analysis of Vegetables. --Of Sap. --Mucilage, or Gum. --Sugar. --Manna, and Honey. --Gluten. --Vegetable Oils. --Fixed Oils, Linseed, Nut, and Olive Oils. --Volatile Oils, forming Essences and Perfumes. --Camphor. --Resins and Varnishes. --Pitch, Tar, Copal, Mastic, &c. --Gum Resins. --Myrrh, Assafœtida, &c. --Caoutchouc, or Gum Elastic. --Extractive colouring Matter; its Use in the Arts of Dyeing and Painting. --Tannin; its Use in the Art of preparing Leather. --Woody Fibre. --Vegetable Acids. --The Alkalies and Salts contained in Vegetables. CONVERSATION XXI. ON THE DECOMPOSITION OF VEGETABLES. 202 Of Fermentation in general. --Of the Saccharine Fermentation, the Product of which is Sugar. --Of the Vinous Fermentation, the Product of which is Wine. --Alcohol, or Spirit of Wine. --Analysis of Wine by Distillation. --Of Brandy, Rum, Arrack, Gin, &c. --Tartrit of Potash, or Cream of Tartar. --Liqueurs. --Chemical Properties of Alcohol. --Its Combustion. --Of Ether. --Of the Acetous Fermentation, the Product of which is Vinegar. --Fermentation of Bread. --Of the Putrid Fermentation, which reduces Vegetables to their Elements. --Spontaneous Succession of these Fermentations. --Of Vegetables said to be petrified. --Of Bitumens: Naphtha, Asphaltum, Jet, Coal, Succin, or Yellow Amber. --Of Fossil Wood, Peat, and Turf. CONVERSATION XXII. HISTORY OF VEGETATION. 243