rds
of his experiments and inventions. The primitive records, covering the
earliest years, were mainly jotted down on loose sheets of paper covered
with sketches, notes, and data, pasted into large scrap-books, or
preserved in packages; but with the passing of years and enlargement of
his interests, it became the practice to make all original laboratory
notes in large, uniform books. This course was pursued until the Menlo
Park period, when he instituted a new regime that has been continued
down to the present day. A standard form of note-book, about eight and
a half by six inches, containing about two hundred pages, was adopted.
A number of these books were (and are now) always to be found scattered
around in the different sections of the laboratory, and in them have
been noted by Edison all his ideas, sketches, and memoranda. Details
of the various experiments concerning them have been set down by his
assistants from time to time.

These later laboratory note-books, of which there are now over one
thousand in the series, are eloquent in the history they reveal of the
strenuous labors of Edison and his assistants and the vast fields
of research he has covered during the last thirty years. They are
overwhelmingly rich in biographic material, but analysis would be
a prohibitive task for one person, and perhaps interesting only to
technical readers. Their pages cover practically every department
of science. The countless thousands of separate experiments recorded
exhibit the operations of a master mind seeking to surprise Nature into
a betrayal of her secrets by asking her the same question in a hundred
different ways. For instance, when Edison was investigating a certain
problem of importance many years ago, the note-books show that on this
point alone about fifteen thousand experiments and tests were made by
one of his assistants.

A most casual glance over these note-books will illustrate the following
remark, which was made to one of the writers not long ago by a member of
the laboratory staff who has been experimenting there for twenty years:
"Edison can think of more ways of doing a thing than any man I ever saw
or heard of. He tries everything and never lets up, even though failure
is apparently staring him in the face. He only stops when he simply
can't go any further on that particular line. When he decides on any
mode of procedure he gives his notes to the experimenter and lets him
alone, only stepping in from