Fig 5 represents a double-convex lens, Fig. 6 a double-concave, and Fig. 7 a concavo-convex or meniscus. By these it is seen that a double-convex lens tends to condense the rays of light to a focus, a double-concave to scatter them, and a concavo-convex combines both powers.英文原著 · 《American Hand Book of the Daguerreotype》
In a sequestered spot where the road hugged close the concave outline of a bushy bluff, Bud slowed and turned out behind a fringe of bushes, and stopped.英文原著 · 《Cabin Fever》
110, p. 500; 114, 587; 117, 477. The same lines looked at directly or backwards seem, in Fig. 1, convex, in Fig. 2 concave. {illust. caption = FIG. 3.}
Still more significant is the illusion in Fig.英文原著 · 《Criminal Psychology》
Eight miles east of the Cibolo ranch-house Ranse loosened the pressure of his knees, and Vaminos stopped under a big ratama tree. The yellow ratama blossoms showered fragrance that would have undone the roses of France. The moon made the earth a great concave bowl with a crystal sky for a lid. In a glade five jack-rabbits leaped and played together like kittens. Eight miles farther east shone a faint star that appeared to have dropped below the horizon. Night riders, who often steered their course by it, knew it to be the light in the Rancho de los Olmos.英文原著 · 《Heart of the West》
picturesque, has a concave curve in the roof, and the eaves project英文原著 · 《Little Rivers》