mination is dangerously low. The adult who tries the
experiment will be inclined to conclude that whatever the illumination,
the proper place for the man who uses diamond type for any purpose is the
penitentiary.

The literature upon this general subject, such as it is, is concerned
largely with its relations with school hygiene. We are bound to give our
children a fair start in life, in conditions of vision as well as in other
respects, even if we are careless about ourselves. The topic of
"Conservation of Vision," in which, however, type-size played but a small
part, was given special attention at the Fourth International Congress of
School Hygiene, held in Buffalo in 1913. Investigations on the subject, so
far as they affect the child in school, are well summed up in the last
chapter of Huey's "Psychology and Pedagogy of Reading." In general, the
consensus of opinion of investigators seems to be that the most legible
type is that between eleven-point and fourteen-point. Opinion regarding
space between lines, due to "leading," is not quite so harmonious. Some
authorities think that it is better to increase the size of the letters;
and Huey asserts that an attempt to improve unduly small type by making
wide spaces between lines is a mistake.

As to the relative legibility of different type-faces, one of the most
exhaustive investigations was that made at Clark University by Miss
Barbara E. Roethlin, whose results were published in 1912. This study
considers questions of form, style, and grouping, independently of mere
size; and the conclusion is that legibility is a product of six factors,
of which size is one, the others being form, heaviness of face, width of
the margin around the letter, position in the letter-group, and shape and
size of adjoining letters. For "tired eyes" the size factor would appear
of overwhelming importance except where the other elements make the page
fantastically illegible. In Miss Roethlin's tables, based upon a
combination of the factors mentioned above, the maximum of legibility
almost always coincides with that of size. These experiments seem to have
influenced printers, whose organization in Boston has appointed a
committee to urge upon the Carnegie Institution the establishment of a
department of research to make scientific tests of printing-types in
regard to the comparative legibility and the possibility of improving some
of their forms. Their effort, so far, has met with no success;