CII A 



215 



CH A 



7'92 inches, consequently equal to 66 feet 

 or 4 poles. 



CHAIN-BOAT, a large boat fitted for get- 

 ting up mooring-'jhains, anchors, &c. 



CHAIN-CABLE. 8>:e CABLE. 



CHAIN-PUMP, a well-known hydraulic 

 machine for raising water. It is usually 

 made from 12 to 25 feet in length, and 

 consists of two collateral square barrels, 

 and an endless chain of pistons of the 

 same form fixed at proper distances. The 

 chain is moved round a coarse kind of 

 wheel-work, the teeth of which are so 

 contrived as to receive one half of the 

 fiat pistons and let them fold in, and they 

 take hold of the links as they rise. Half 

 the pistons are ascending when the ma- 

 chine is at work, and bring up a full bore 

 oi water in the pump. 



CHAIN-SHOT, two balls chained toge- 

 ther, used chiefly at sea, to be shot against 

 vessels to damage the rigging. 



CHAIN-TIMBER, a piece of timber in 

 breadth equal to the length and breadth 

 of a brick, used for strengthening brick- 

 walls, by insertion in the middle of the 

 height of the story. 



CHAIN-WALES. In a ship, broad and 

 thick planks projecting from a ship's sides, 

 abreast and behind the masts, for the 

 purpose of extending the shrouds, for 

 better supporting the masts, and prevent- 

 ing the shrouds from damaging the gun- 

 wale by rubbing. Every mast has its 

 chain- wales. 



CHAIN'WORK, a peculiar style of textile 

 fabric, to which hosiery and tambouring 

 belong. 



CHAIR, a moveable seat. This name is 

 used to designate a pedestal or socket of 

 cast-iron used upon railways, for receiv- 

 ing and securing the rails upon the blocks, 

 to which they are fastened by oak tree- 

 nails. The chair for receiving the ends 

 of two rails is termed a joint or double 

 chair, being larger than the simple or tn- 

 ttrmediatt chairs. 



CHAISE-LONGUE (French), a sort of sofa 

 open at one end. 



CHAL'AZA, XaX?. A hailstone. 1. In 

 botany, a point marked on the interior 

 tunic of the seeds of some plants, which 

 answers to the insertion of their umbili- 

 cal cord. It is sometimes coloured, as in 



the lemon and orange. 2. The two 



white bodies attached to the membrane 

 which covers the yolk of an egg, are 

 called chalaza or grandines. 



CHALA'O.B, a name applied to the two 

 twisted cords attached to the yolk of an 

 egg, to maintain it uppermost in every 

 position of the egg. 



CHALCBDO'NT, a snb-species of quartz, 

 called also white agate, named from Chal- 

 cedon, a town in Asia Minor. 



CBALCEDO'NYX, a variety of agate, in 

 which white and grey layers alternate. 



CHAL'CIDES, a genus of Scincoideans. 

 They are elongated lizards resembling 

 serpents ; but the scales are rectangular, 

 forming transverse bands which do not 

 encroach on each other. 



CHALCID'I.B, a tribe of hymenopterous 

 insects, of which the genus Chalcii is the 

 type. 



CHALCI'DICUM. In ancient architecture, 

 a large building for administering justice ; 

 sometimes the tribunal itself. 



CHAL'CIS, a genus of hymenopterous in- 

 sects so named from their being decorated 

 with extremely brilliant metallic colours 

 (x>.xot, brass"). 



CHALCOG'RAPHT, the art of engraving 

 on brass; yat/.xos, brass, and ?*$*>> to 

 write. 



CHAL'DROX, a dry English measure ; 36 

 coal bushels make a chaldron, and 21 chal- 

 drons make a score. The bushel contains 

 2217'6 cubic inches, but when heaped it 

 contains 2615'5 cubic inches, making the 

 chaldron 58'65 cubic feet. The Newcastle 

 chaldron contains 53 cwt., and is just 

 double of the London chaldron. 



CHALK, a white earthy limestone, (car- 

 bonate of lime), Sp. gr. 2'3. It usually 

 contains an inconsiderable portion of silex 

 and iron. 



CHALK FORMATION. This term is ap- 

 plied, in the nomenclature of geology, to 

 a group of deposits very dissimilar in 

 their compositions, but agreeing in the 

 character of the organic remains which 

 they contain, and referrible to the same 

 epoch of formation. These strata are dis- 

 tinguished into : 1. The Maestricht beds; 

 2. The upper chalk with flints; 3. The 

 lower chalk without flints; 4. The 

 upper green sand; 5. The gault; 6. The 

 lower green sand. The whole of these 

 are marine deposits, and their greatest 

 aggregate thickness in England may be 

 estimated at from 600 to 1000 feet. 



CHALK-STONE, a calcareous concretion 

 in the hands and feet of violently affected 

 gouty persons. 



CHAL'LENGE. In law, an exception to 

 jurors ; the claim p f a party that certain 

 jurors shall not sit in trial upon him or 

 his cause. The right of challenge is given, 

 both in civil and criminal cases, for cer- 

 tain causes which are supposed to disqua- 

 lify a juror to be an impartial judge. The 

 word is Norm., calenge, an accusation. 

 Among sportsmen, the opening cry of 

 hounds at first finding the scent of the 

 game, is called the challenge, and the 

 same name is given to any invitation, 

 verbal or written, of parties, to decide a 

 controversy by. duel. 



CHA'MA, a genus of inequivalved adhe- 

 ring bivalves, forming the type of the fa- 

 mily Chamacea. 



CHAMACE'A, a family of bivalves placed 

 by Lamarck in the order Dimyaria, and 



