His contributions to Anthropology were an essay on the _Physical Education of the Child_, a lecture on _The Origin and Colour of the Negro_, and a treatise on _The Orang-outang and some other species of Apes_; but only his work on the facial angle has attained permanent fame. His early inclinations were towards art, and he was carefully trained in drawing, painting, and architecture; and it was in the interests of Art, not of Anthropology, that the researches which resulted in his determination of the facial angle came to be undertaken. This he describes in his preface to his lectures:— At the age of eighteen, my instructor, Charles Moor the younger, to whose attention and care I am indebted for any subsequent progress I may have made in this art, set me to paint one of the beautiful pieces of Van Tempel, in which there was the figure of a negro, that by no means pleased me. In his colour he was a negro, but his features were those of a European. As I could neither please myself nor gain any proper directions, I desisted from the undertaking. By critically examining the prints taken from Guido Reni, C. Marat, Seb. Ricci, and P. P. Rubens, I observed that they, in painting the countenances of the Eastern Magi, had, like Van Tempel, painted black men, but they were not Negroes. To obtain the necessary facial effects distinguishing the Negro from the European, Camper devised his system of measurements. He drew a line from the aperture of the ear to the base of the nose, and another from the line of the junction of the lips (or, in the case of a skull, from the front of the incisor teeth) to the most prominent part of the forehead. “If,” he said, “the projecting part of the forehead be made to exceed the 100th degree, the head becomes mis-shapen and assumes the appearance of hydrocephalus or watery head. It is very surprising that the artists of Ancient Greece should have chosen precisely the maximum, while the best Roman artists have limited themselves to the 95th degree, which is not so pleasing. The angle which the facial or characteristic line of the face makes,” he continued, “varies from 70 to 80 degrees in the human species. All above is resolved by the rules of art; all below bears resemblance to that of apes. If I make the facial line lean forward, I have an antique head; if backward, the head of a Negro. If I still more incline it, I have the head of an ape; and if more still, that of a dog, and then that of an idiot.” Camper’s facial angle may be of service to Art, but since the points from which the lines are drawn are all variable, owing to the disturbing influence of other factors, such as an increased length of face or an unusually prominent brow-ridge, it cannot form an accurate measurement for Anthropology. It was severely criticised by Blumenbach, Lawrence, and Prichard, but adopted in France, and by Morton in America.