Stone also compared eighteen systems where there was supervision of the work by superintendents or supervisors as well as by principals with four systems where the principals and teachers had no such help. The scores in his tests were very much lower in the four latter cities. THE HYGIENE OF THE EYES IN ARITHMETIC We have already noted that the task of reading and copying numbers is one of the hardest that the eyes have to perform in the elementary school, and that it should be alleviated by arranging much of the work so that only answers need be written by the pupil. The figures to be read and copied should obviously be in type of suitable size and style, so arranged and spaced on the page or blackboard as to cause a minimum of effort and strain. [Illustration: FIG. 26.--Type too large.] [Illustration: FIG. 27.--12-point, 11-point, and 10-point type.] _Size._--Type may be too large as well as too small, though the latter is the commoner error. If it is too large, as in Fig. 26, which is a duplicate of type actually used in a form of practice pad, the eye has to make too many fixations to take in a given content. All things considered, 12-point type in grades 3 and 4, 11-point in grades 5 and 6, and 10-point in grades 7 and 8 seem the most desirable sizes. These are shown in Fig. 27. Too small type occurs oftenest in fractions and in the dimension-numbers or scale numbers of drawings. Figures 28, 29, and 30 are samples from actual school practice. Samples of the desirable size are shown in Figs. 31 and 32. The technique of modern typesetting makes it very difficult and expensive to make fractions of the horizontal type (1 3 5 - - - 4, 8, 6) large enough without making the whole-number figures with which they are mingled too large or giving an uncouth appearance to the total. Consequently fractions somewhat smaller than are desirable may have to be used occasionally in textbooks.[19] There is no valid excuse, however, for the excessively small fractions which often are made in blackboard work. [19] A special type could be constructed that would use a large type body, say 14 point, with integers in 10 or 12 point and fractions much larger than now. [Illustration: FIG. 28.--Type of measurements too small. This is a picture of Mary's garden. How many feet is it around the garden?] [Illustration: FIG. 29.--Type too small.] [Illustration: FIG. 30.--Numbers too small and badly designed.] [Illustration: FIG. 31.--Figure 28 with suitable numbers.] [Illustration: FIG. 32.--Figure 30 with suitable numbers.]