74 THE POPULAR SCIENCE MONTHLY. 



duced the Carystian, Deucalian, Synnadic, and Hierapolitic marbles. 

 The quarries of Tenos are still worked to some extent, but those of 

 Scyros and Naxos remain almost as the ancients left them. 



Of the black marbles of antiquity that now called nero antico, or 

 black antique, was the most celebrated. It is more intensely black 

 than any marble now quarried, the black marbles of France appear- 

 ing almost gray beside it. It occurs only in sculptured pieces, and 

 its origin is unknown ; but Faujas discovered a quarry which had 

 been worked by the ancients, about two leagues from Spa, not far 

 from Aix-la-Chapelle, the marble of which closely resembles the an- 

 cient specimens. The largest masses known of nero antico are two 

 columns in the church of Regina Coeli at Rome, but there are also 

 some fine specimens in the Museum of the Capitol and in other col- 

 lections. Some suppose it to be identical with the marmor Lucul- 

 lum^ which was introduced at Rome by Lucullus in the first century 

 B. c, according to Pliny from Melos (another reading is Chios), but 

 according to other authorities from Egypt or Libya, whence it is 

 sometimes called marmor Lihycum. Pliny says that Marcus Scaurus 

 had pillars of it thirty-eiglit feet high in the atrium of his house. The 

 Chian marble, a deep, transparent black, sometimes variegated with 

 other colors, was quarried on Mount Pelinaeus, in the island of Chios. 

 A fine black marble was quarried on Mount Taenarus, in Laconia, and 

 in the island of Lesbos, and a blue-black marble in Lydia. One of 

 the most beautiful of the antique breccias, the African breccia, has a 

 deep-black ground, variegated with fragments of grayish white and 

 deep red or purplish wine-color. The grand antique breccia consists 

 of large fragments of black marble united by veins of shining white. 

 Columns of this and of African breccia are in the Paris Museum, but 

 their quarries are unknown. 



ON THE WOITDERFIJL DIYISIBILITY OF GOLD AND 



OTHER METALS. 



By ALEXANDER E. OUTERBRIDGE, Je., 



ASSAY LABOEATOKY, UNITED STATES MINT, PHILADELPHIA. 



IT is both curious and interesting to notice how frequently original 

 investigators, working from different standpoints, and with en- 

 tirely dissimilar objects in view, will, independently of each other, 

 accumulate a mass of observations corroborative of some one phys- 

 ical law, but Avhich require to be collated in order to reveal their 

 mutual relations. 



The motive of this paper is to collect together several observa- 

 tions illustrating the divisibility of gold (made either as the direct 



