The aim of the author has been to supply the requirements of those who are anxious to obtain an elementary knowledge of the primary principles of Electric Lighting, but who have neither the time nor the inclination to read the' subject at the length at which it is generally treated in text-books, and who moreover have not the mathematical aptitude and acquaintance with mechanical terms and methods that are indispensable to anyone who desires to grasp the complete theory and full details of this important though compara tively new branch of science. As a stepping-stone to treatises of a more advanced and elaborate nature, this little work may likewise be found use ful by those who purpose making a more extended study of the subject.