He determined from about the age of fifteen that his calling was to be such as would be useful to mankind. He studied mathematics, science, and astronomy whenever he could find books to borrow. He was from there on interested in these scientific and mathematical subjects his entire life. When Burt was about sixteen, his father sent him to school for six weeks to learn science and mathematics, which he continued on his own, even though his duties at home and on the farm were equal to other boys in his age group. Burt recalled this as he wrote about himself when he was sixty-two years old.