o exist in
natural relation to each other. It has always seemed to me that he goes
to the core of things at once."

Although nothing less than results from actual experiments are
acceptable to him as established facts, this view of Edison may
also account for his peculiar and somewhat weird ability to "guess"
correctly, a faculty which has frequently enabled him to take short
cuts to lines of investigation whose outcome has verified in a most
remarkable degree statements apparently made offhand and without
calculation. Mr. Upton says: "One of the main impressions left upon me,
after knowing Mr. Edison for many years, is the marvellous accuracy of
his guesses. He will see the general nature of a result long before it
can be reached by mathematical calculation." This was supplemented by
one of his engineering staff, who remarked: "Mr. Edison can guess better
than a good many men can figure, and so far as my experience goes, I
have found that he is almost invariably correct. His guess is more than
a mere starting-point, and often turns out to be the final solution of
a problem. I can only account for it by his remarkable insight and
wonderful natural sense of the proportion of things, in addition to
which he seems to carry in his head determining factors of all
kinds, and has the ability to apply them instantly in considering any
mechanical problem."

While this mysterious intuitive power has been of the greatest advantage
in connection with the vast number of technical problems that have
entered into his life-work, there have been many remarkable instances
in which it has seemed little less than prophecy, and it is deemed worth
while to digress to the extent of relating two of them. One day in
the summer of 1881, when the incandescent lamp-industry was still
in swaddling clothes, Edison was seated in the room of Major Eaton,
vice-president of the Edison Electric Light Company, talking over
business matters, when Mr. Upton came in from the lamp factory at
Menlo Park, and said: "Well, Mr. Edison, we completed a thousand
lamps to-day." Edison looked up and said "Good," then relapsed into
a thoughtful mood. In about two minutes he raised his head, and said:
"Upton, in fifteen years you will be making forty thousand lamps a day."
None of those present ventured to make any remark on this assertion,
although all felt that it was merely a random guess, based on the
sanguine dream of an inventor. The business had not then really