NOTE C.—If the pupils are old enough, they may be shown that vertical lines cannot be parallel, but only seem so on account of their shortness and nearness to each other. * * * * * NOTE D.—This definition may be considered objectionable because _rhomboid_ means like a rhomb. That the more general figure, the rhomboid, has been named from the more restricted one, the rhomb, is unfortunate, because it interferes with the symmetry of the nomenclature. The rhomb possesses all the properties of the rhomboid, and should, therefore, when these are considered, be called by the same name; its additional property entitles it to a name which should comprehend the other names. If the rectangle had been called a squaroid, the difficulty would have been repeated. * * * * * NOTE E.—If teachers consider it desirable, they may require the class to prove, by way of corollary, such propositions as assert the parallelism of the lines when the interior alternate angles are equal, when the opposite exterior and interior angles are equal, &c., in continuation of what has already been done. ------------------------------------------------------------------------ TOWNSEND’S ANALYSIS OF THE CONSTITUTION OF THE UNITED STATES A CHART of 52 pages on one roller, designed to hang in Class-Rooms. An exposition of the Constitution; making it one of the most interesting as it is the most important study for our young men. TOWNSEND’S ANALYSIS OF CIVIL GOVERNMENT. A TEXT-BOOK TO ACCOMPANY THE CHART OF THE CONSTITUTION WELLS’ SCIENTIFIC SERIES. CONTAINING THE LATEST RESEARCHES IN PHYSICAL SCIENCES, AND THEIR PRACTICAL APPLICATION TO EVERY-DAY LIFE. Science of Common Things. Natural Philosophy. Principles of Chemistry. First Principles of Geology. GRAY’S BOTANICAL SERIES, By ASA GRAY, Fisher Professor of Natural Science in Harvard University. The leading Botanist in America. They have no equal. “How Plants Grow.” Lessons in Botany. Manual of Botany (New Edition). Gray’s Lessons and Manual in 1 vol. Gray’s Field, Forest and Garden Botany. Gray’s School and Field Book of Botany. [Consisting of Gray’s Lessons, and Field, Forest and Garden Botany, bound in 1 vol.] Manual, with Mosses. Structural and Systematic Botany. BRYANT & STRATTON’S BOOK-KEEPING SERIES. The best TEXT-BOOKS ever prepared on this subject.