(Catena), a series of several rings or links, fitted into one another.
There are chains of divers matters, sizes, forms, and for divers uses.—Ports, rivers, streets, &c. are closed with iron chains; rebellious cities are punished by taking away their chains and barriers.
The arms of the kingdom of Navarre are, Chains Or, in a field of Gules. The occasion hereof is referred to the kings of Spain leagued against the Moors; who, having gained a celebrated victory against them in 1212, in the distribution of the spoils the magnificent tent of Miralumun fell to the king of Navarre, as being the first that broke and forced the chains thereof.
A gold chain is one of the ornaments or badges of the dignity of the chief magistrates of a city, as the mayor of London, the provost and bailies of Edinburgh, &c.—Something like this obtained among the ancient Gauls: the principal ornament of their person in power and authority was a gold chain, which they wore on all occasions; and even in battle, to distinguish them from the common soldiers.
Chain also denotes a kind of string, of twisted wire; serving to hang watches, tweeter cases, and other valuable toys upon. The invention of this piece of curious work is owing to the English; whence, in foreign countries, it is denominated the English chain. These chains are usually either of silver or gold, some of gilt copper; the thread or wire of each kind to be very fine.—For the fabric, or making of these chains; a part of the wire is folded into little links of an oval form; the longest diameter about three lines; the shortest one. These, after they have been exactly soldered, are again folded into two; and then bound together or interwoven, by means of several other little threads of the same thickness; some whereof, which pass from one end to the other, imitate the warp of a stuff; and the others, which pass transverse, the woof. There are at least four thousand little links in a chain of four pendants; which are by this means bound so equally, and withal so firmly together, that the eye is deceived, and takes the whole to consist of one entire piece.
Chain is also a kind of measure in France, in the trade of wood for fuel. There are chains for wood by tale, for wood by the rope, for faggots, for cleft wood, and for round sticks. There are also chains for measuring the sheaves of all sorts of corn, particularly with regard to the payment of tithes; for measuring pottles of hay, and for measuring horses. All these are divided into feet, inches, hands, &c. according to the use they are designed for.
in surveying, is a measure, consisting of a certain number of links of iron wire, usually a hundred; serving to take the dimensions of fields, &c. This is what Mercenne takes to be the arvipedium of the ancients.
The chain is of various dimensions, as the length or number of links varies: that commonly used in measuring land, called Gunter's chain, is in length four poles or perches; or sixty-five feet, or a hundred links; each link being seven inches $\frac{9}{10}$$. Whence it is easy to reduce any number of those links to feet, or any number of feet to links.
This chain is entirely adapted to English measure; and its chief convenience is in finding readily the numbers contained in a given field. Where the proportions of square feet and acres differ, the chain, to have the same advantages as Gunter's chain, must also be varied. Thus, in Scotland, the chain ought to be of 74 feet, or 24 Scotch ells, if no regard be had to the difference between the Scotch and English foot; but if regard be had to this difference, the Scotch chain ought to consist of 74$\frac{3}{4}$ English feet, or 74 feet four inches and $\frac{3}{4}$ of an inch. This chain being divided into an hundred links, each of these will be $\frac{9}{100}$ inches.
That ordinarily used for large distances, is in length 100 feet; each link one foot. For small parcels, as gardens, &c. is sometimes used a small chain of one pole, or 16 feet and a half length; each link one inch $\frac{9}{10}$.
Some in lieu of chains use ropes; but these are liable to several irregularities, both from the different degrees of moisture, and of the force which stretches them. Schwenterus, in his Practical Geometry, tells us, he has observed a rope sixteen feet long reduced to fifteen in an hour's time, by the mere falling of a hoar-frost. To obviate these inconveniences, Wolfius directs, that the little strands whereof the rope consists be twisted contrariwise, and the rope dipped in boiling hot oil, and when dry, drawn through melted wax. A rope thus prepared will not get or lose any thing in length, even though kept under water all day.
CHAIN Pump. See Pump.
CHAIN-Shot, two bullets with a chain between them. They are used at sea to shoot down yards or masts, and to cut the throats or rigging of a ship.
Top CHAIN, on board a ship, a chain to sling the sail yards in time of battle, in order to prevent them from falling down when the ropes by which they are hung happen to be shot away or rendered incapable of service.
CHAIN Wales, or Channels, of a ship, (porteboîffres), are broad and thick planks projecting horizontally from the ship's outside, abreast of and somewhat behind the masts. They are formed to extend the throats from each other, and from the axis or middle line of the ship, so as to give a greater security and support to the masts, as well as to prevent the throats from damaging the gunwale, or being hurt by rubbing against it. Every mast has its chain wales, which are either built above and below the second deck ports in a ship of the line; they are strongly connected to the side by knees, bolts, and standards, besides being confined thereto by the chains, whose upper ends pass through notches on the outer edge of the chain wales, so as to unite with the throats above.