urpentine off, act on the
residue with all the solvents that were used on the residue, using for
the first the solvent which is least likely to dissolve a great part
of it. By thus manipulating the various solvents you will be
enabled probably to separate the crude asphalt into several distinct
hydrocarbons. Put each in a bottle after it has been dried, and label
the bottle with the process, etc., so we may be able to duplicate it;
also give bottle a number and describe everything fully in note-book."

"Destructively distil the following substances down to a point just
short of carbonization, so that the residuum can be taken out of the
retort, powdered, and acted on by all the solvents just as the asphalt
in previous page. The distillation should be carried to, say, 600
degrees or 700 degrees Fahr., but not continued long enough to wholly
reduce mass to charcoal, but always run to blackness. Separate the
residuum in as many definite parts as possible, bottle and label, and
keep accurate records as to process, weights, etc., so a reproduction of
the experiment can at any time be made: Gelatine, 4 lbs.; asphalt, hard
Cuban, 10 lbs.; coal-tar or pitch, 10 lbs.; wood-pitch, 10 lbs.;
Syrian asphalt, 10 lbs.; bituminous coal, 10 lbs.; cane-sugar, 10 lbs.;
glucose, 10 lbs.; dextrine, 10 lbs.; glycerine, 10 lbs.; tartaric acid,
5 lbs.; gum guiac, 5 lbs.; gum amber, 3 lbs.; gum tragacanth, 3 Lbs.;
aniline red, 1 lb.; aniline oil, 1 lb.; crude anthracene, 5 lbs.;
petroleum pitch, 10 lbs.; albumen from eggs, 2 lbs.; tar from passing
chlorine through aniline oil, 2 lbs.; citric acid, 5 lbs.; sawdust of
boxwood, 3 lbs.; starch, 5 lbs.; shellac, 3 lbs.; gum Arabic, 5 lbs.;
castor oil, 5 lbs."

The empirical nature of his method will be apparent from an examination
of the above items; but in pursuing it he leaves all uncertainty
behind and, trusting nothing to theory, he acquires absolute knowledge.
Whatever may be the mental processes by which he arrives at the
starting-point of any specific line of research, the final results
almost invariably prove that he does not plunge in at random; indeed,
as an old associate remarked: "When Edison takes up any proposition
in natural science, his perceptions seem to be elementally broad and
analytical, that is to say, in addition to the knowledge he has acquired
from books and observation, he appears to have an intuitive apprehension
of the general order of things, as they might be supposed t