, and tipped with
black. Coatis are gregarious and arboreal in habit, and feed on birds,
eggs, lizards and insects. They are common pets of the Spaniards in
South America. (See CARNIVORA.)

COB, a word of unknown origin with a variety of meanings, which the _New
English Dictionary_ considers may be traced to the notions of something
stout, big, round, head or top. In "cobble," e.g. in the sense of a
round stone used in paving, the same word may be traced. The principal
uses of "cob" are for a stocky strongly built horse, from 13 to 14 hands
high, a small round loaf, a round lump of coal, in which sense "cobble"
is also used, the fruiting spike of the maize plant, and a large nut of
the hazel type, more commonly known as the cob-nut.

"Cobbler," a patcher or mender of boots and shoes, is probably from a
different root. It has nothing to do with an O. Fr. _coubler_, Mod.
_coupler_, to fasten together. In "cobweb," the web of the spider, the
"cob" represents the older _cop, coppe_, spider, cf. Dutch _spinnekop_.

COBALT (symbol Co, atomic weight 59), one of the metallic chemical
elements. The term "cobalt" is met with in the writings of Paracelsus,
Agricola and Basil Valentine, being used to denote substances which,
although resembling metallic ores, gave no metal on smelting. At a later
date it was the name given to the mineral used for the production of a
blue colour in glass. In 1735 G. Brandt prepared an impure cobalt metal,
which was magnetic and very infusible. Cobalt is usually found
associated with nickel, and frequently with arsenic, the chief ores
being speiss-cobalt, (Co, Ni, Fe)As2, cobaltite (q.v.), wad, cobalt
bloom, linnaeite, Co3S4, and skutterudite, CoAs3. Its presence has also
been detected in the sun and in meteoric iron. For the technical
preparation of cobalt, and its separation from nickel, see NICKEL. The
metal is chiefly used, as the oxide, for colouring glass and porcelain.

Metallic cobalt may be obtained by reduction of the oxide or chloride in
a current of hydrogen at a red heat, or by heating the oxalate, under a
layer of powdered glass. As prepared by the reduction of the oxide it is
a grey powder. In the massive state it has a colour resembling polished
iron, and is malleable and very tough. It has a specific gravity of 8.8,
and it melts at 1530 deg. C. (H. Copaux). Its mean specific heat between
9 deg. and 97 deg. C. is 0.10674 (H. Kopp). It is permanent in dry air,
but in the