STEREOGRAPHY is that branch of knowledge which demonstrates the properties. and teaches the whole doc trine of regularly defined solids. It explains the rules fur constructing the superficies in piano, so as to form the entire solid, or to cover its surface. It also slims how to form any section thereof, or to find any angles or inclinations relating to two or more of its surfaces ; or any angles upon any one of its surfaces. formed by a line and adjacent side of the surface, by having the proper data given according to what may be required.
Mr Hamilton has denominated the principles of per spective by the term stercography, contrary to the usage of other authors. Perspective is only a branch of the doctrine of solids; and all that this branch teaches, is only the method., for finding the sections of pyrand is and cones, tire eye being considered as the vertex, the original object the base of tire pyramid or cone, and tire pieture to be drawn a section thereof; the term is there lore of too general application, perspective being only a branch of stereography.
The eleventh and twelfth books of the Element., of Euclid belong to sterrography : these mav be [oohed upon as the theory of tire doctrine of solids, and to WC shall refer our readers for the original prop( roes; but for their practical applications to useful propertio; in life, it is rather singular that so little has been done in this respect. The present article is entirely new. It is of the greatest importance in the various mechanical departments of architecture. The geometrical prin ciples in masonry, carpentry, joinery, and the ()diet useful branches of the building art, are entirely depen dent upon it : in short, tn• cutting or individual pieces of timber in the art of carpentry, and tire formation of separate stones in masonry, is only tme application of stereography to practice.
To the acquirement of these arts this branch of geo metry is therefore indispensible ; and, is it is a key to the whole, no farther apology for its introduction is necessary.