This tool, a facial gonimeter, was used to measure the facial angle of heads and skulls. From its readings, many believed, the quality of intelligence and ability could be measured. The facial angle, invented by Petrus Camper in the 1770s, was applied by Dr. Samuel Morton in his 1839 book, Crania Americana. This book, which portrayed Indians of the Americas as inherently violent and incapable of education, employed the facial angle to argue its point. Morton's book also provided scientific justification for Andrew Jackson's Indian Removal Act, which turned America's original inhabitants into refugees and led to genocide.