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_]