has been considered one of Edison's
greatest inventions, but it does not compare in importance and value
with the electric incandescent burner light. This required many
thousands of experiments and tests to get a filament that would burn
long enough in a vacuum to make the light sufficiently cheap to compete
with petroleum or gas. During all the years that he was experimenting on
different metals and materials for the electric light which was yet to
be, in a literal sense, the light of the world, he had men hunting in
all countries for exactly the right material out of which the carbon
filament now in use is made. Thousands of kinds of wood, bamboo and
other vegetable substances were tried. The staff made over fifty
thousand experiments in all for this one purpose. This illustrates the
art and necessity of taking pains, one of Mr. Edison's greatest
characteristics. The story of producing electric light would fill a big
volume.

"When the proper filament was discovered and applied there was great
rejoicing in the laboratory and a regular orgy of playing pranks and
fun.

"The philosophers say we measure time by the succession of ideas. If
this is true the time must have been longer and seemed shorter in
Edison's laboratories than anywhere else. The great inventor seldom
carried a watch and seemed not to like to have clocks about.

"Soon after he was married, the story went the rounds of the press that
within an hour or two after the ceremony, Edison became so engrossed
with an invention that he forgot that it was his wedding day. Edison has
declared this story to be untrue.

"'That's just one of the kind of yarns,' said the inventor laughing,
'that the reporters have to make up when they run short of news. It was
the invention of an imaginative chap who knows I'm a little
absent-minded. I never forgot that I was married.

"'But there was an incident that may have given a little color to such a
story. On our wedding day a lot of stock tickers were returned to the
factory and were said to need overhauling.

"'About an hour after the ceremony I was reminded of those tickers and
when we got to our new home, I told my wife about them, adding that I
would like to walk down to the factory a little while and see if the
boys had found out what was the matter.

"'She consented and I went down and found an assistant working on the
job. We both monkeyed with the machines an hour or two before we got
them to rights. Then I we