From twenty to thirty-five per cent. of molasses are separated in the refining of raw sugars; and it is supposed, that a considerable part of it, probably two-thirds, are formed by the high heat used in the concentration of the sirup. In order to prevent so great a quantity of molasses, different plans have been recommended. That of Howard is highly spoken of. It consists in surrounding the sugar-boiler with oil or steam at a high temperature, instead of exposing it, as heretofore, or the mode usually adopted, to the naked fire. The boiler is covered at top, and, by means of an air-pump, the air is exhausted, and the pressure of the atmosphere being removed, ebullition takes place at a lower temperature. No blood is used in Mr. H.'s process, instead of which, the clarification is performed by means of canvass filters, adding previously a pasty mixture of gypsum and alumina, made by saturating a solution of alum with quicklime. He does not employ clay, as is done in whitening the sugar; but, in its place, makes use of very pure saturated sirup. He uses animal charcoal, (bone black), which has the property of destroying vegetable colouring matter. Wilson's process for refining sugar possesses some advantages. It will be found in the 34th volume of the _Repertory of Arts_. The patent filtering apparatus of Sutherland is highly approved. The chemical properties of sugar are the following: It is very soluble in water, both hot and cold; it forms with water a sirup, which on standing will crystallize, forming the candied sugar. It is not acted upon by oxygen gas. It is capable of combining with, and, according to some chemists, of neutralizing acids and alkalies. It is decomposed by nitric acid with effervescence, being converted into oxalic and malic acids. Tartaric, acetic, and oxalic acids prevent it from crystallizing. It unites with lime and strontian, but is partially decomposed by barytes. It combines also with oxide of lead, which it precipitates from its solution, forming, as it is called, a saccharate of lead. Alcohol has some action on it, and also hydrosulphurets, sulphurets, and phosphurets of alkalies and alkaline earths. On the application of heat, it melts, swells, becomes brownish-black, and exhales a peculiar odour, which we have mentioned, and, at a red heat, takes fire. Lastly, though possessed of some general and specific characters, it differs, in some of its properties, according to the substance from which it is obtained. _Sect. XXIII. Of Sal Prunelle._