Further uses are developed in the process of refining. This latter is exceedingly simple. The crude oil is placed in an iron retort connected with a coil of pipe in a vessel of cold water. Heat is then applied to the retort, when the process of distillation commences. The first product is a light-colored, volatile substance, sometimes called naphtha, that is very explosive. This substance is used in the place of spirits of turpentine in the preparation of paints and varnishes, and, after further treatment, in removing paints and grease from clothing. The next product from the retort is the refined fluid for illumination. This is of a yellow color, with a bluish tinge and powerful odor, requiring further treatment before it is ready for the lamp. This treatment consists in placing it in a cistern lined with lead, and agitating it with a portion of sulphuric acid. The acid and impurities having subsided, the oil is drawn off, and further agitated with soda lye, and finally with water, when it is ready for use. After this a coarse oil for the lubrication of machinery is produced. Paraffine is another product resulting from this distillation. It is a white, tasteless, and inodorous substance, used in the manufacture of candles. The residuum in the retort may be applied to various useful purposes. It is sometimes used as fuel, and sometimes takes the place of coal tar in the arts, and by chemical processes is made to yield products useful in the laboratory and in the manufactory. But the aesthetics connected with this distillation must not be passed by in silence. On a bright, sunshiny day we see a bright globule of petroleum rising from the bottom of the stream. As it reaches the surface of the water it disperses, and, as it glides away, all the colors of the rainbow are reflected from its undulating surface. 'What radiant changes strike th' astonished sight! What glowing hues of mingled shade and light! Not equal beauties gild the lucid west With parting beams o'er all profusely drest, Not lovelier colors paint the vernal dawn, When Orient dews impearl th' enamelled lawn, Than in its waves in bright suffusion flow, That now with gold empyreal seem to glow; Now in pellucid sapphires meet the view, And emulate the soft celestial hue; Now beams a flaming crimson on the eye, And now assume the purple's deeper dye. But here description clouds each shining ray-- What terms of art can Nature's powers display?'