PATENTED TELEPHONY A REVIEW OF THE PATENTS PERTAINING TO APPARATUS. BY THE American Electrical Engineering Association. CHICAGO, ILL., 1897. COPYRIGHT, 1897, BY AMERICAN ELECTRICAL ENGINEERING ASSOCIATION. ALL RIGHTS RESERVED. PRESS OF EDWARD KEOGH PRINTING CO. CHICAGO, ILL. 52974 APR 5 1900 TR 6392930 •AM3 A INTRODUCTORY. The SMALL investment in telephone construction yields, at present prices, large profits. unknown quantity is the patent situation. One class of capitalists declines the risk; the other recklessly plunges into blind speculation. The former is unnecessarily timid; the latter foolhardy. Proper examination will open to the first a golden opportunity and save the second from becoming dangerously involved. This treatise is designed for both these classes of investors, as well as a reference book for the inventor, engineer and patent lawyer. The United States patents now in force which cover devices and systems used in telephony, are in number about four thousand. The following pages illustrate merely the salient features, the high lights in the art, which are revealed by the study of both expired and unexpired patents. The labor involved in this research has been excessive. It is presumable there are errors and omissions; but we believe it gives a fairly correct view of what, to a great majority of people, appears a hopeless tangle. TABLE OF CONTENTS. 1 Bell Patent No. 174465 (4). Berliner Patent No. 233969 (11). Ber- liner Patent No. 463569 (14). Summary (20). Decision of Judge Carpenter (20). Decision of Court of Appeals (21). Decision of Supreme Court (21). Decision of Supreme Court, 1888, Bell Pat- ent (25). Parallel Columns, Berliner 1880 and 1891 Patents (28 Cheever, No. 208463 (40). Eldred, No. 303714 (41). Watson, No. 256258 (44). Watson, No. 280266 (45). Scribner, No. 266319 (46). Firman, No. 283334 (46). Kellogg, No. 247199 (47). Kellogg, No. 308315 (48). Scribner, No. 330058 (49). Scribner, No. 330059 (50). Scribner, No. 330060 (50). Scribner, No. 330061 (50). Scribner, No. Shaw, No. 220874 (54). Trunking Principle (54). Childs, No. 225797 List of Sabin & Hampton Patents (72). Sabin & Hampton, No. Haskins, No. 299926 (81). Lytle & McCoy, No. 313828 (82). Shaw, Connolly & McTighe, No. 222458 (86). Strowger, No. 447918 (87). LIST OF PLATES. Plates 1 and 2. Patent of A. G. Bell, No. 174465 Plate 3. Patent of Emile Berliner, No. 233969 Plates 4 and 5. Patent of Emile Berliner, No. 463569 Patents of Emile Berliner (parallel columns) Plate 6. Patent of C. A. Cheever, No. 208463 Plate 7. Patent of H. H. Eldred, No. 303714 (diagram) Plates 8 and 9. Patent of Thos. A. Watson, No. 256258 Plate 10. Patent of L. B. Firman, No. 283334 Plate 11. Patent of M. G. Kellogg, No. 247199 Plate 12. Patent of C. E. Scribner, No. 330058 (sheet 2) Plates 13 and 14. Patent of C. E. Scribner, No. 300144 Plate 15. Trunking Principle (diagram) 92 |