s, but that was in the earlier years when the
strenuous scenes of Menlo Park were repeated in the new quarters. Edison
and his closest associates were accustomed to carry their labors far
into the wee sma' hours, and when physical nature demanded a respite
from work, a short rest would be obtained by going to bed on a cot.
One would naturally think that the wear and tear of this intense
application, day after day and night after night, would have tended to
induce a heaviness and gravity of demeanor in these busy men; but on
the contrary, the old spirit of good-humor and prankishness was ever
present, as its frequent outbursts manifested from time to time. One
instance will serve as an illustration. One morning, about 2.30, the
late Charles Batchelor announced that he was tired and would go to bed.
Leaving Edison and the others busily working, he went out and returned
quietly in slippered feet, with his nightgown on, the handle of a
feather duster stuck down his back with the feathers waving over his
head, and his face marked. With unearthly howls and shrieks, a l'Indien,
he pranced about the room, incidentally giving Edison a scare that made
him jump up from his work. He saw the joke quickly, however, and joined
in the general merriment caused by this prank.

Leaving the main building with its corps of busy experimenters, and
coming out into the spacious yard, one notes the four long single-story
brick structures mentioned above. The one nearest the Valley Road is
called the galvanometer-room, and was originally intended by Edison to
be used for the most delicate and minute electrical measurements. In
order to provide rigid resting-places for the numerous and elaborate
instruments he had purchased for this purpose, the building was equipped
along three-quarters of its length with solid pillars, or tables, of
brick set deep in the earth. These were built up to a height of about
two and a half feet, and each was surmounted with a single heavy slab of
black marble. A cement floor was laid, and every precaution was taken to
render the building free from all magnetic influences, so that it would
be suitable for electrical work of the utmost accuracy and precision.
Hence, iron and steel were entirely eliminated in its construction,
copper being used for fixtures for steam and water piping, and, indeed,
for all other purposes where metal was employed.

This room was for many years the headquarters of Edison's able
assistant,