For several years he delivered gratuitous lectures on the Natural
History of Animals, Light, Electricity, the Seasons, Hydraulics,
Eclipses, etc. His knowledge of machinery enabled him admirably to
illustrate these lectures by models of his own construction; and his
successful experiments and simple teaching added much to the practical
knowledge of his operatives.

He proposed to occupy the space between the common schools and the
college halls by carrying, so far as might be practicable, the design of
the Rumford Lectures of Harvard into the community of the actual workers
of common life.

In the mean time he discharged his official duties efficiently, and the
superintendence of the schools of Lowell was also added to his labors.
He never relinquished, during these busy years, the design formed in his
college days of furnishing to the children of the country a series of
text-books on the _inductive plan_ in mathematics.

His "Algebra upon the Inductive Method of Instruction," appeared in
1825, and his "Sequel to Intellectual Arithmetic" in 1836. He regarded
the "Sequel" as a book of more merit and importance than the "First
Lessons."

He also published a series of selections from Miss Edgeworth's stories,
in a suitable form for reading exercises for the younger classes of
the Lowell schools, in the use of which the teachers were carefully
instructed.

In May, 1827, he was elected a Fellow of the American Academy of
Sciences. For several years he was a member of the Examining Committee