Daniel Davis, Jr., and his <i>Manual of Magnetism</i>

In the preface to his 1842 Manual of Magnetism, the Boston scientist and manufacturer of electrical apparatus, Daniel Davis, Jr., wrote, “Magnetism and Electricity have become related sciences within such a short a period, and their growth has been so rapid, that many important facts which have been observed have not been collected in any scientific treatise, and the amount of unwritten knowledge has been constantly increasing.” His book served as a companion to the apparatus that he manufactured, and it supplied the scientific background to experiments using these instruments. This paper traces the development of some of these instruments and explains their operation, showcasing their ingenuity and inspiring demonstrations for contemporary physics classes. A great deal of his apparatus still exists in museums and the storage closets of schools, college, and universities. I urge you to seek it out and husband it.