The Practical Astronomer Comprising illustrations of light and colours--practical descriptions of all kinds of telescopes--the use of the equatorial-transit--circular, and other astronomical instruments, a particular account of the Earl of Rosse's large telescopes, and other topics connected with astronomy

CHAPTER III.

Chapter 4101 wordsPublic domain

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.