Beschreibung
As subservient to the improvements above alluded to, we must acknowledge the agency of numerous contrivances by means of maps, charts, engravings, and copious statistical tables, and also of a distinction of type between what is more and what is less essential in the subject matter of a treatise. Several of these contrivances, as well as of the more general improvements; have been extended to historical productions, as books designed for education and especially ?eat help has been derived from the last named particular  the use of difierentsnzes of type.