The Invention Of The Incandescent Lamp - 6

The Invention Of The Incandescent Lamp - 6

The date of this interesting visit to Ansonia is fixed by an inscription made by Edison on
a glass goblet which he used. The legend in diamond scratches runs: "Thomas A. Edison,
September 8, 1878, made under the electric light." Other members of the party left
similar memorials, which under the circumstances have come to be greatly prized. A
number of experiments were witnessed in arc lighting, and Edison secured a small
Wallace-Farmer dynamo for his own work, as well as a set of Wallace arc lamps for
lighting the Menlo Park laboratory. Before leaving Ansonia, Edison remarked,
significantly: "Wallace, I believe I can beat you making electric lights. I don't think you
are working in the right direction." Another date which shows how promptly the work
was resumed is October 14, 1878, when Edison filed an application for his first lighting
patent: "Improvement in Electric Lights." In after years, discussing the work of Wallace,
who was not only a great pioneer electrical manufacturer, but one of the founders of the
wire-drawing and brass-working industry, Edison said: "Wallace was one of the earliest
pioneers in electrical matters in this country. He has done a great deal of good work, for
which others have received the credit; and the work which he did in the early days of
electric lighting others have benefited by largely, and he has been crowded to one side
and forgotten." Associated in all this work with Wallace at Ansonia was Prof. Moses G.
Farmer, famous for the introduction of the fire-alarm system; as the discoverer of the
self-exciting principle of the modern dynamo; as a pioneer experimenter in the electricrailway
field; as a telegraph engineer, and as a lecturer on mines and explosives to naval
classes at Newport. During 1858, Farmer, who, like Edison, was a ceaseless investigator,
had made a series of studies upon the production of light by electricity, and had even
invented an automatic regulator by which a number of platinum lamps in multiple arc
could be kept at uniform voltage for any length of time. In July, 1859, he lit up one of the
rooms of his house at Salem, Massachusetts, every evening with such lamps, using in
them small pieces of platinum and iridium wire, which were made to incandesce by
means of current from primary batteries. Farmer was not one of the party that memorable
day in September, but his work was known through his intimate connection with
Wallace, and there is no doubt that reference was made to it. Such work had not led very
far, the "lamps" were hopelessly short- lived, and everything was obviously
experimental; but it was all helpful and suggestive to one whose open mind refused no
hint from any quarter.
At the commencement of his new attempts, Edison returned to his experiments with
carbon as an incandescent burner for a lamp, and made a very large number of trials, all
in vacuo. Not only were the ordinary strip paper carbons tried again, but tissue- paper
coated with tar and lampblack was rolled into thin sticks, like knitting-needles,
carbonized and raised to incandescence in vacuo. Edison also tried hard carbon, wood
carbons, and almost every conceivable variety of paper carbon in like manner. With the
best vacuum that he could then get by means of the ordinary air-pump, the carbons would
last, at the most, only from ten to fifteen minutes in a state of incandescence. Such results
were evidently not of commercial value.
Edison then turned his attention in other directions. In his earliest consideration of the
problem of subdividing the electric current, he had decided that the only possible solution
lay in the employment of a lamp whose incandescing body should have a high resistance
combined with a small radiating surface, and be capable of being used in what is called
"multiple arc," so that each unit, or lamp, could be turned on or off without interfering
with any other unit or lamp. No other arrangement could possibly be considered as
commercially practicable.
The full significance of the three last preceding sentences will not be obvious to laymen,
as undoubtedly many of the readers of this book may be; and now being on the threshold
of the series of Edison's experiments that led up to the basic invention, we interpolate a
brief explanation, in order that the reader may comprehend the logical reasoning and
work that in this case produced such far-reaching results.