Boiling solvent vapor goes up the
large side arm to the condensor.

Condensed liquid drips down to center
compartment holding cellulose thimble
containing the sample, e.g. spinach.

When deep enough, liquid drains by siphon
and returns to the round bottom flask.

Repeat for hours or days as continous extraction,
reusing the same solvent.

Soluble material ends up in the round bottom flask.
Insoluble material is left in the thimble.
Separation success depends on choice of solvent.