The Invention Of The Incandescent Lamp - 4

The Invention Of The Incandescent Lamp - 4

The reader may have deemed this sketch of the state of the art to be a considerable

digression; but it is certainly due to the subject to present the facts in such a manner as to

show that this great invention was neither the result of improving some process or device

that was known or existing at the time, nor due to any unforeseen lucky chance, nor the

accidental result of other experiments. On the contrary, it was the legitimate outcome of a

series of exhaustive experiments founded upon logical and original reasoning in a mind

that had the courage and hardihood to set at naught the confirmed opinions of the world,

voiced by those generally acknowledged to be the best exponents of the art--experiments

carried on amid a storm of jeers and derision, almost as contemptuous as if the search

were for the discovery of perpetual motion. In this we see the man foreshadowed by the

boy who, when he obtained his books on chemistry or physics, did not accept any

statement of fact or experiment therein, but worked out every one of them himself to

ascertain whether or not they were true.

Although this brings the reader up to the year 1879, one must turn back two years and

accompany Edison in his first attack on the electric-light problem. In 1877 he sold his

telephone invention (the carbon transmitter) to the Western Union Telegraph Company,

which had previously come into possession also of his quadruplex inventions, as already

related. He was still busily engaged on the telephone, on acoustic electrical transmission,

sextuplex telegraphs, duplex telegraphs, miscellaneous carbon articles, and other

inventions of a minor nature. During the whole of the previous year and until late in the

summer of 1877, he had been working with characteristic energy and enthusiasm on the

telephone; and, in developing this invention to a successful issue, had preferred the use of

carbon and had employed it in numerous forms, especially in the form of carbonized

paper.

Eighteen hundred and seventy-seven in Edison's laboratory was a veritable carbon year,

for it was carbon in some shape or form for interpolation in electric circuits of various

kinds that occupied the thoughts of the whole force from morning to night. It is not

surprising, therefore, that in September of that year, when Edison turned his thoughts

actively toward electric lighting by incandescence, his early experiments should be in the

line of carbon as an illuminant. His originality of method was displayed at the very

outset, for one of the first experiments was the bringing to incandescence of a strip of

carbon in the open air to ascertain merely how much current was required. This

conductor was a strip of carbonized paper about an inch long, one-sixteenth of an inch

broad, and six or seven one-thousandths of an inch thick, the ends of which were secured

to clamps that formed the poles of a battery. The carbon was lighted up to incandescence,

and, of course, oxidized and disintegrated immediately. Within a few days this was

followed by experiments with the same kind of carbon, but in vacuo by means of a handworked

air-pump. This time the carbon strip burned at incandescence for about eight

minutes. Various expedients to prevent oxidization were tried, such, for instance, as

coating the carbon with powdered glass, which in melting would protect the carbon from

the atmosphere, but without successful results.