Extraordinary appearance of the coast of France from Hastings--Appearance of a ship seen by Captain Colby, beyond the coast of Caithness--Scoresby’s view of his father’s ship when beyond the horizon--Phenomenon near the Himalaya mountains--Bell Rock light-house--Summary statement of the diversified effects of refraction--Reflections on the beneficent and diversified effects produced by the law of refraction--It increases the length of the day, particularly in the polar regions--Is the cause of that splendour which appears in the objects around us--Quantity of refraction in respect to terrestrial objects, and its utility--Its effects may be more diversified in other worlds _page_ 53-63. CHAPTER III. ON THE REFRACTION OF LIGHT THROUGH SPHERICAL TRANSPARENT SUBSTANCES, OR LENSES. Refraction the foundation of optical instruments--Various forms of lenses--_Parallel_, _converging_, and _diverging_ rays--Illustrated by diagrams--_Concave_ lenses, their effects, and how to find their focal distances--IMAGES formed by convex lenses--Illustrated by experiments--Principles in relation to images formed by lenses--Their magnifying powers, &c. _page_ 63-75. REFLECTIONS DEDUCED FROM THE PRECEDING SUBJECT. Property of the rays of light in forming _images_ of objects--Wonderful results and discoveries which have flowed from this property--in relation to our knowledge of the scenery of the heavens and the minute parts of nature--and of our views of the attributes of Deity _page_ 75-80. CHAPTER IV. ON THE REFLECTION OF LIGHT. Nature of reflection--Plane, convex, and concave speculums--Angle of reflection--Reflection of objects from plane mirrors, illustrated by figures--_Reflection by Convex and Concave mirrors_--Properties of _convex_ mirrors, and the purposes to which they are applied. Properties of concave speculums, and their utility--Of the _images_ formed by concave speculums--Illustrated by a variety of figures and experiments--Their power of magnifying and burning--Amusing deceptions produced by--Resemblance between the properties of convex lenses, and concave mirrors--Quantity of light reflected by polished surfaces _page_ 81-106. UNCOMMON APPEARANCES OF NATURE PRODUCED BY THE COMBINED INFLUENCE OF REFLECTION AND REFRACTION. _Fata Morgana_--The Mirage--Inverted images of ships seen in the horizon--Appearance of Dover castle at Ramsgate--Spectre of the Brocken--Scenes in the Highlands of Scotland--Large cross seen at Migné in France--Dr. Wollaston’s illustrations of such phenomena--Utility of science in dissipating superstitious fears _page_ 106-118. REMARKS AND REFLECTIONS IN REFERENCE TO THE PHENOMENA DESCRIBED ABOVE. Light, the beauty of the universe, and a symbol of the Divinity--In other worlds it may produce an infinite variety of sublime scenery _page_ 118-122. CHAPTER V. SECT. 1.--ON THE COLOURS OF LIGHT.