Before becoming professor of mathematics in the Academy and College of Philadelphia, Thomas Pratt was a student in the Mathematical School in the Academy of Philadelphia. After completing his studies there in 1757, he became a tutor in the English School, and later the writing master and usher there. In 1759, Pratt was asked by the trustees to substitute for Theophilus Grew, the mathematics professor at the time, who had fallen ill and was often unable to conduct class. Since no one was properly qualified to take over the Mathematical School upon Grew’s death in November of 1759, Pratt was promoted to professor of mathematics until a permanent replacement for Grew could be found.
Because of Pratt’s former position as writing master, a number of boys from the Latin and English Schools constantly came to his classes seeking to be taught to write. As a consequence, Pratt found it very difficult to teach and, in October of 1760, announced that he could no longer serve in the Mathematical School. After it was agreed that Hugh Williamson would take Pratt’s place, Pratt was once again made writing master. When Williamson was made a trustee in 1763, and hence forced to give up his professorship, Pratt was rehired as professor of mathematics, because of his previous experience and the lack of another candidate. He remained in the post until 1766, when Thomas Dungan successfully applied for the position. Pratt then returned to the place of writing master once more, the trustees believing that this was a suitable position for him because he was an apprentice in town and hence had other business to attend to besides teaching.
In the February 22, 1757, Trustees’ Minutes, a list of students in the Mathematical School reveals that a Charles Pratt completed his studies in the same year as Thomas Pratt. It is likely that the two were related. If they were brothers, they were most likely the children of Henry Pratt and Rebecca Pratt, of Philadelphia. If this is the case, Thomas Pratt was born on January 29, 1745, and died in 1800.
There have also been claims that Thomas Pratt was the same man as Dr. Thomas Pratt, who received an M.B. (the equivalent of an M.D.) from the Medical Department in 1769 and lived in Georgetown, South Carolina. Dr. Pratt’s 1770-1774 letters to Benjamin Rush are available at the Historical Society of Pennsylvania.