fraught ing

[FREIGHT, v.] Going to make up the freight or cargo; as, the fraughting bricks. Fraun-hō-fer (au as ow), s. [A distinguished optician of Munich.] (See the compound.) Fraunhofer's lines, s. pl . Optics: Certain dark lines discovered by Wollaston, in 1802, in the solar spectrum, but first described in detail by Fraunhofer. If a pencil of solar rays be admitted through a narrow slit into a dark room, and then the slit be looked at through a prism of flint gla very free from flaws, the lines will be seen delicately traced in large numbers parallel to the edge of the prism, and at very unequal intervals. Fraunhofer names the most remarkable of them A, a , B, C, D, E, b , F, G, and H. A is at the beginning of the red ray, B in the middle, and cat the boundary between it and the orange, D in the orange, E in the green, F in the blue, G in the indigo, and H in the violet: a is in the red and b in the green. About 3,000 lines have since been discriminated; some are fixed in position, others are variable. The latter are sometimes called atmospheric or telluric lines, being considered by certain physicists to be due to the absorption of the air. The study of these lines has since led to the introduction of the method of analysis called spectral analysis. ( Ganot .)