Samuel Adams, to oblige the Trustees, had originally agreed to extend his stay at the Academy from the date of his resignation in August, 1821, until October 11. When it became clear that he was unable to carry on. the school reconvened under the supervision of his assistant, Mr. Taylor G. Worcester. The Trustees in general were apparently in accord with one of their number, the Reverend Elijah Parish, who wrote that it was ". . . important that a Preceptor should immediately occupy the premises . . ." Promptly on the eleventh of October, therefore, Nehemiah Cleaveland was inducted into office. Once again the Board was fortunate in its selection; for nineteen years Mr. Cleaveland was to provide firm, vigorous, and intelligent leadership. Yet a perverse fortune must have ordained that his very success should lay the foundation of ultimate disappointment. The Academy, like the son of Daedalus, exulted too much in its progress and in attempting to soar too high contributed to its own downfall. Nevertheless, credit for the progress. not blame for the downfall, belongs to Nehemiah.
Twenty-five boys made up the population of the school upon Mr. Cleaveland's arrival. Though the Trustees had voted to provide an assistant when the number topped thirty, the Preceptor, in spite of rapid increase beyond this figure, did not for some years see fit to take advantage of the authorization. Instead he made use of the more talented older boys to help with the tutelage of the younger, arranging that the tuition charge for his student-assistants be remitted in return for their efforts.
In the next nineteen years, of the more than 400 boys who came there to study, a total of 360 graduated from Dummer Academy. Such success prompted the Trustees to investigate extensively a number of plans "for increasing the usefulness of the school." The first called for the creation of an agricultural department which was to be endowed jointly by the Academy and the Commonwealth of Massachusetts. The Dummer Farm did, indeed, offer a promising site for such an experiment. For a time prospects for the addition appeared good, but in the end they failed. Hope was revived a few years later (in 1834) and once more faltered.