Doubleday
ABNER, an American military officer; born in Ballston Spa, N. Y., June 26, 1819. He was graduated at the United States Military Academy in 1842, rising to the rank of colonel in 1870 (brevet lieutenant-colonel in 1865).
He was second in command at Fort Sumter in 1861, firing the first gun in its defense, and he greatly distinguished himself at Gettysburg. He died at Mendham, N. J., Jan. 26, 1893. DOUBLE STANDARD, in economics the phrase double standard is used to
DOUBLE STARS and MULTIPLE STARS, stars which appear single to the naked eye, but in the telescope are resolved into two or more close together. There is no limit to the distance between these, but those whose components are more than 15" or 20" apart are not generally included in catalogues of double stars, and those whose distance is much less than 1" require telescopes of large aperture to separate them distinctly. The discovery and measurement of the position-angles and distances of the components of these objects form almost a distinct department of astronomical observation, to which many able astronomers have given nearly all their lives. These measurements have shown that many of these doubles are true binary systems, the two components revolving round their common center of gravity in periods that range from 10 to 12 years, to unknown thousands and obeying, so far as these motions can show, the same law of gravitation that regulates the motion of the solar system. Sir William Herschel was the great pioneer in the field of discovery of these objects, but his measures were of comparatively little accuracy, and the elder Struve may be considered as the first astronomer to lay the foundation of this branch research. The field of first discovery of these double stars has thus far been principally covered by five astronomers, and most of the known doubles are usually called by the catalogue number of the works or discovery lists of these five men, with a distinguishing letter for each, although it is very generally the custom to call the star by the catalogue number of the elder Struve if it is contained in the "Mensuræ Micrometrice." These five astronomers, with their distinguishing letters, are as follows:
Herschel, Sir William.
Struve, F. G. W...
Herschel, Sir John.
Struve, Otto.
Burnham, S. W...
H.
Σ. h.
Ο Σ. .β..
DOUBS (dö), a department of France, having Switzerland on its E. frontier.
Its surface is traversed by four chains of the Jura. The land is arable, but much the greater part is covered with DOUGHERTY forests. Maize, potatoes, hemp, flax, are the principal crops. Much dairy produce is made into Gruyère cheese. The minerals include iron, lead, and marble. Pop. about 290,000. The river Doubs rises in the department to which it gives its name, flows first N. E., then N. W., till it joins the Saône at Verdun-sur-Saône; length, 250 miles.