on of all his great inventions has been signalized by patient,
persistent, and incessant effort which, recognizing nothing short of
success, has resulted in the ultimate accomplishment of his ideas.
Optimistic and hopeful to a high degree, Edison has the happy faculty of
beginning the day as open-minded as a child--yesterday's disappointments
and failures discarded and discounted by the alluring possibilities of
to-morrow.

Of all his inventions, it is doubtful whether any one of them has
called forth more original thought, work, perseverance, ingenuity, and
monumental patience than the one we are now dealing with. One of his
associates who has been through the many years of the storage-battery
drudgery with him said: "If Edison's experiments, investigations, and
work on this storage battery were all that he had ever done, I should
say that he was not only a notable inventor, but also a great man. It is
almost impossible to appreciate the enormous difficulties that have been
overcome."

From a beginning which was made practically in the dark, it was not
until he had completed more than ten thousand experiments that he
obtained any positive preliminary results whatever. Through all
this vast amount of research there had been no previous signs of the
electrical action he was looking for. These experiments had extended
over many months of constant work by day and night, but there was no
breakdown of Edison's faith in ultimate success--no diminution of his
sanguine and confident expectations. The failure of an experiment simply
meant to him that he had found something else that would not work, thus
bringing the possible goal a little nearer by a process of painstaking
elimination.

Now, however, after these many months of arduous toil, in which he
had examined and tested practically all the known elements in numerous
chemical combinations, the electric action he sought for had been
obtained, thus affording him the first inkling of the secret that he
had industriously tried to wrest from Nature. It should be borne in
mind that from the very outset Edison had disdained any intention of
following in the only tracks then known by employing lead and sulphuric
acid as the components of a successful storage battery. Impressed with
what he considered the serious inherent defects of batteries made of
these materials, and the tremendously complex nature of the chemical
reactions taking place in all types of such cells, he determin