A text book of geometrical drawing : abridged from the octavo edition : for the use of schools in which the definitions and rules of geometry are familiarly explained, the practical problems are arranged from the most simple to the more complex, and in their description technicalities are avoided as much as possible : with an introduction to isometrical drawing : and an essay on linear perspective and shadows ... (1849)
A. B is much less thanthe length of the chord A, C, as in the diagram, thecentres for striking the curves will be some distancebeyond the base, as shewn by the rods ; the joints allradiate to the opposite centres. Fig. 2.—The Equilateral Arch. When the span D. jE, and the chords D. F and E.F form… … W Umifi^ Ulm.av. 3c Sons. PLATE XXIV. 79 Fig. 3.—The Depressed Arch Has its centres within the base of the arch, the chordsbeing shorter than the span ; the joints radiate to thecentres respectively. Note.—^There are no definite proportions for Gothic arches,except for the equilateral; they vary…
