in a review of William Herschel's A Treatise on Sound, Quarterly Review, Vol. 44, No. 88 (January-February 1831), p. 476 http://books.google.com/books?id=742veo7MzswC&printsec=titlepage#PPA476,M1.
also quoted by Brewster himself in his Treatise on Optics http://books.google.com/books?id=opYAAAAAMAAJ&printsec=frontcover#PPR4,M1 and by Dionysius Lardner as frontispiece or presentation of his works (see for example: Popular lectures on science and art http://books.google.com/books?id=uZ9LAAAAMAAJ&pg=PA3, Cabinet Cyclopaedia http://books.google.com/books?id=5T43oHhqyxUC&pg=RA1-PT7).
Context: It is not easy to devise a cure for such a state of things (the declining taste for science). The most obvious remedy is to provide the educated classes with a series of works on popular and practical science, freed from mathematical symbols and technical terms, written in simple and perspicuous language, and illustrated by facts and experiments which are level to the capacity of ordinary minds.