This notebook covers the period June-December 1891. It contains transcriptions by Arthur E. Kennelly of material from the rough record books used by experimenters in the Galvanometer Room. There are notes, drawings, tables, and calculations regarding a variety of electrical experiments, including tests of meters, condensers, fan motors, alternators, and dynamos. In addition, there are extensive notes and design drawings relating to electric traction, including tests of Edison General Electric street car motors, and data regarding low-voltage street railway systems. Also included are comparisons of Westinghouse, Thomson-Houston, and Edison transformers; data regarding the electromagnetic properties of iron; and theoretical notes concerning physics, electricity, and mathematics. Among the experimenters whose work appears in this book are Alfred J. Thompson and Arthur Hoopes. At the end of the book is a subject index; it appears at the beginning of the book in the digital edition. The front cover is marked \"V\"" and \""1891.\"" The book contains 159 numbered pages. Some pages were removed before the book was paginated. Numerous graphs, blueprints, tissue copies, photographs, and other items have been pasted into the book."