“In this well-written work Mr. Cox has given a popular description of the eye, and the adaptation of spectacles to correct constitutional defects or organic disease: by attention to a few simple rules which he lays down, any one may effectually fortify himself against the artful representations of dishonest dealers in spectacles “made to sell.” The public is indebted to Mr. Cox for having exposed the tricks of the insidious marauders in several towns in which they were practising their impositions, and his tract contains some correspondence between him and several eminent surgeons, from which it appears that they had been represented as vouching for pretended improvements in spectacles, of which they either knew nothing at all, or with regard to which they themselves had been deceived by the fraudulent pretenders.” _Christian Advocate._ “This is a useful little work, treating on a subject of universal importance—namely, defining the laws by which deficiency of sight can be assisted, founded on scientific principles, and aided by extensive observation in a long practice; we would recommend a perusal of the pamphlet to such as are about to seek the aid of the maker of spectacles.” _Morning Advertiser._ “This little _brochure_ is correct, ingenious, and useful: moreover, it is valuable as exposing the gross ignorance, impostures, and frauds of Jews, pedlars, and other locomotive quacks. The humbug of _amber_ spectacles, _coloured_ pebbles, clarified crystals, &c., is here thoroughly exploded. Altogether the information in this pamphlet is well deserving of attention.” _Aldine Magazine._ “An amusing exposure of the puffing and swindling systems pursued by some self-styled opticians, from which besides may be gathered a good deal of sound, practical information.” _Era._ “If every body’s sight were impaired, we should strongly hope that this little treatise would become universally known; but as we have reason to believe there are some people in the world who can see a little, we shall only address ourselves to the former, to whom we can confidently recommend the perusal of this talented work. Besides a great deal of necessary and sound information on the use and nature of spectacles, we find a number of _exposés_ of the tricks pursued by many unprincipled persons styling themselves opticians, which is put forth by the author in a very distinct manner.” _Blackwood’s Lady’s Magazine._ CONTENTS. CHAPTER I. Page. Invention of Spectacles and Burning Glasses 1 Examination of Opticians—Artful Impositions 2 Duke of Wellington and the Bubble Schemes 4 Basis of Optical Knowledge—Physiology of the Eyes 6 CHAPTER II. Failure of Sight and the Application of Spectacles 10