k by the Pennsylvania
Railroad, and over three thousand persons took advantage of the
opportunity to go out there and witness this demonstration for
themselves. In this great crowd were many public officials and men of
prominence in all walks of life, who were enthusiastic in their praises.

In the mean time, the mind that conceived and made practical this
invention could not rest content with anything less than perfection,
so far as it could be realized. Edison was not satisfied with paper
carbons. They were not fully up to the ideal that he had in mind. What
he sought was a perfectly uniform and homogeneous carbon, one like the
"One-Hoss Shay," that had no weak spots to break down at inopportune
times. He began to carbonize everything in nature that he could lay
hands on. In his laboratory note-books are innumerable jottings of the
things that were carbonized and tried, such as tissue-paper, soft paper,
all kinds of cardboards, drawing-paper of all grades, paper saturated
with tar, all kinds of threads, fish-line, threads rubbed with tarred
lampblack, fine threads plaited together in strands, cotton soaked in
boiling tar, lamp-wick, twine, tar and lampblack mixed with a proportion
of lime, vulcanized fibre, celluloid, boxwood, cocoanut hair and shell,
spruce, hickory, baywood, cedar and maple shavings, rosewood, punk,
cork, bagging, flax, and a host of other things. He also extended his
searches far into the realms of nature in the line of grasses, plants,
canes, and similar products, and in these experiments at that time
and later he carbonized, made into lamps, and tested no fewer than six
thousand different species of vegetable growths.

The reasons for such prodigious research are not apparent on the face of
the subject, nor is this the occasion to enter into an explanation, as
that alone would be sufficient to fill a fair-sized book. Suffice it
to say that Edison's omnivorous reading, keen observation, power of
assimilating facts and natural phenomena, and skill in applying the
knowledge thus attained to whatever was in hand, now came into full play
in determining that the results he desired could only be obtained in
certain directions.

At this time he was investigating everything with a microscope, and one
day in the early part of 1880 he noticed upon a table in the laboratory
an ordinary palm-leaf fan. He picked it up and, looking it over,
observed that it had a binding rim made of bamboo, cut from the outer