icle. A
thousand and one instances could be quoted in illustration; but as
they would tend to change the form of this narrative into a history of
economy in manufacture, it will suffice to mention but one, and that a
recent occurrence, which serves to illustrate how closely he keeps in
touch with everything, and also how the inventive faculty and instinct
of commercial economy run close together. It was during Edison's winter
stay in Florida, in March, 1909. He had reports sent to him daily
from various places, and studied them carefully, for he would write
frequently with comments, instructions, and suggestions; and in one
case, commenting on the oiling system at the cement plant, he wrote:
"Your oil losses are now getting lower, I see." Then, after suggesting
some changes to reduce them still further, he went on to say: "Here is a
chance to save a mill per barrel based on your regular daily output."

This thorough consideration of the smallest detail is essentially
characteristic of Edison, not only in economy of manufacture, but in
all his work, no matter of what kind, whether it be experimenting,
investigating, testing, or engineering. To follow him through the
labyrinthine paths of investigation contained in the great array of
laboratory note-books is to become involved in a mass of minutely
detailed searches which seek to penetrate the inmost recesses of nature
by an ultimate analysis of an infinite variety of parts. As the reader
will obtain a fuller comprehension of this idea, and of Edison's
methods, by concrete illustration rather than by generalization, the
authors have thought it well to select at random two typical instances
of specific investigations out of the thousands that are scattered
through the notebooks. These will be found in the following extracts
from one of the note-books, and consist of Edison's instructions to be
carried out in detail by his experimenters:

"Take, say, 25 lbs. hard Cuban asphalt and separate all the different
hydrocarbons, etc., as far as possible by means of solvents. It will be
necessary first to dissolve everything out by, say, hot turpentine, then
successively treat the residue with bisulphide carbon, benzol, ether,
chloroform, naphtha, toluol, alcohol, and other probable solvents.
After you can go no further, distil off all the solvents so the asphalt
material has a tar-like consistency. Be sure all the ash is out of the
turpentine portion; now, after distilling the t