However, I recovered from this blow, and soon after Mr. Gardiner G. Hubbard, afterwards Mr. Bell’s father-in-law, offered me an interest in Bell’s patents if I would give up my work at Williams’ and devote my time to the telephone. I accepted, although I wasn’t altogether sure it was a wise thing to do from a financial standpoint. My contract stipulated that I was to work under Mr. Bell’s directions, on the harmonic telegraph as well as on the speaking telephone, for the two men who were paying the bills still thought there was something in the former invention, although very little attention had been given to its vagaries after the June 2nd discovery. [Illustration: 1876 BELL TELEPHONE _Telephone Apparatus Patented in 1876 by Prof. Bell, Models Made from Figure 7 in Bell’s Original Patent_] I moved my domicile from Salem to another room on the top floor at 5 Exeter Place, giving us the entire floor, and as Mr. Bell had lost most of his pupils by wasting so much of his time on telephones, he could devote nearly all his time to the experimenting. Then followed a period of hard and continuous work on the invention. I made telephones with every modification and combination of their essential parts that either of us could think of. I made and we tested telephones with all sizes of diaphragms made of all kinds of materials—diaphragms of boiler iron several feet in diameter, down to a miniature affair made of the bones and drum of a human ear, and found that the best results came from an iron diaphragm of about the same size and thickness as is used to-day. We tested electro magnets and permanent magnets of a multitude of sizes and shapes, with long cores and short cores, fat cores and thin cores, solid cores and cores of wire, with coils of many sizes, shapes and resistances, and mouthpieces of an infinite variety. Out of the hundreds of experiments there emerged practically the same telephone you take off the hook and listen with to-day, although it was then transmitter as well as receiver. [Illustration: _Reprint from the Boston Advertiser describing the Telephone Talk between Boston and Cambridgeport, October 9, 1876_] TELEPHONY. AUDIBLE SPEECH CONVEYED TWO MILES BY TELEGRAPH. PROFESSOR A. GRAHAM BELL’S DISCOVERY—SUCCESSFUL AND INTERESTING EXPERIMENTS—THE RECORD OF A CONVERSATION CARRIED ON BETWEEN BOSTON AND CAMBRIDGEPORT.