He could adjust it in reverse, to serve as a microscope, and he observed insects by this means.
(he; observed; insects) (He; could adjust; it; to serve as a microscope) Context(He could adjust,List([0, 15))):(He; could adjust it to serve; as a microscope)
He could adjust,List([0, 15))
he He He
observed could adjust could adjust it to serve
insects
it to serve as a microscope
as a microscope