CASTING CASTOR-OIL. 



87 



Sand-casting- between flasks is used for more com- 

 plex articles than the former ; such, for instance, as 

 if they were cut into two or more pieces, (provided 

 the cutting planes were parallel to each other,) each 

 separate piece might be cast in open sand. The 

 flasks are iron frames, furnished with four handles, 

 by which they may be lifted, and having iron points 

 fitting into holes prepared in the other flask, for join- 

 ing them accurately together. The under flask be- 

 ing placed upon a board filled with sand, and the 

 sand rammed tight into it, the workman then takes 

 the pattern and presses one half of it into the sand, 

 and smooths the sand up to the sides of it with a 

 trowel ; he then sets the empty flask over the other, 

 adjusting its points to the holes, and after sprinkling 

 some sand which has been burnt (to free it from mois- 

 ture) over the sand hi the under flask, he fills the up- 

 per one with sand, and rams it down ; he next, with 

 a piece of wood, put through the sand in the upper 

 flask, makes a hole to pour the metal through. The 

 upper flask, with the sand in it, is then raised off by 

 men by the handles, or in large works by a crane, 

 and the pattern lifted out. The flask is then put on 

 again, and heavy weights laid upon it to keep it 

 down ready for casting. It must be observed, that 

 at every uppermost point of large moulds, a small 

 hole must be bored through the sand in the upper 

 flask, to allow the ratified air to escape out of the 

 mould when melted metal is poured in. 



Loam-casting is used for bulky, hollow articles, 

 such as cylinders, large pipes, cauldrons, boilers, &c. , 

 mid is conducted in this manner: if, for instance, a 

 large cylinder is to be cast, a mould has first to be 

 nade as follows : To a beam hi the roof of the foun- 

 dery is affixed a perpendicular spindle, with three or 

 four holes through it, to fix an iron arm hi, at differ- 

 ent heights, by means of a nut. This arm has two 

 bars placed at such a distance as to be capable of re- 

 ceiving a wooden plank, which can be firmly secured 

 to them by means of two clamps. The operation is 

 then begun by laying an iron ring upon the ground, 

 and adjusting it so as to be concentric to the spindle. 

 A cylinder of brick-bats, or clay and wet loam (in- 

 stead of mortar), is then to be built upon it, some 

 inches less in diameter than the intended cylinder, for 

 which this is to form a core : the brick-bats are then 

 to be firmly bound together with iron hoops, annealed 

 wire, c., and a fire is then to be lighted within it to 

 dry it. When the loam used between the bricks is 

 dry, a coating of loam is spread over it, and is per- 

 fectly smoothed, by causing the edge of the per- 

 pendicular board to revolve round it. This coat 

 makes it of the proper size for the inside of the cy- 

 linder to be cast, and is called the core of the mould. 

 Another cylinder is built, plastered, and smoothed in 

 the same way, except that no hoops are used, whose 

 diameter is the same as the outside of the cylinder to 

 be cast. When this is finished, it is covered with a 

 coating of charcoal, ground up with water, like paint, 

 laid on with a brush, and a thin coating of loam is 

 laid on ; this is bound round with hoops, and to these 

 four hooks are fixed to lift it by ; a thick coat of loam 

 and hair is then laid over it. When all these are dry, 

 a man then gets down into the cylinder, and with 

 a small pick pulls down all the bricks in the inside 

 cylinder, and then with a trowel cuts away all the 

 loam, leaving the inside of the external cylinder 

 (which is called the mould) quite smooth. This is 

 effected by the coating of powdered charcoal, which 

 prevents the two coats of loam from adhering toge- 

 ther. A deep pit is now dug, in some convenient 

 part of the foundery, into which the core is let down 

 by a crane. The core being placed in the pit, the 

 mould is let down after it by the same means ; and, 

 when they are adjusted, the sand is thrown and ram- 



med round about half the height ; a flat cover of 

 dried loam is then put on the top of the mould and 

 core, and round pieces of wood are put in the holes 

 which had before been made in the cover for pouring 

 the metal in at. The burying of the mould is then 

 completed. When it is all levelled, the sticks which 

 keep open the holes for the metal are carefully with- 

 drawn, and small channels made from the furnace 

 to allow the melted iron to find its way to the mould. 

 When the form is more complicated, as in pear-like 

 shapes, &c., where a man cannot be introduced to 

 pick out the bricks, the mould must be sawn in half, 

 perpendicularly, with a fine saw, to get it off. It is 

 then put together again round the core, and the 

 crack plastered up with loam. 



C ASTLEREAGH, a barony in the county of Down, 

 Ireland. The castle stands on the summit of a Dan- 

 ish rath, and was once the seat of an O'Neil. It is 

 now the property of the marquis of Downshire. The 

 barony gives the title of viscount to the marquis of 

 Londonderry. 



CASTLEREAGH, LORD. See Londonderry. 



CASTOR and POLLUX ; the sons of Tyndarus, 

 king of Lacedaemon and Leda, or, according to some, 

 of Jupiter and Leda. The fable runs, that Leda 

 brought forth two eggs, one of which contained Pol- 

 lux and Helen, the other Castor and Clytemnestra. 

 Pollux and Helen being the offspring of Jupiter, 

 were immortal ; but Castor and Clytemnestra were 

 begotten by Tyndarus, and mortal. The two bro- 

 thers were inseparable companions, equally brave and 

 spirited, and attached to each other with the fondest 

 affection. Castor was particularly skilled in the art 

 of breaking horses, and Pollux in boxing and wrest- 

 ling. They were among the heroes of the Argonau- 

 tic expedition, in which they acquired divine honours ; 

 for, a terrible tempest having arisen on the voyage, 

 and all, with loud voices, calling on the gods to save 

 them, there suddenly appeared over the heads of Cas- 

 tor and Pollux two star-like meteors, and the tempest 

 subsided. From this tune, they were the patron dei- 

 ties of mariners, and received the name of Dioscuri ; 

 and from them the name of Castor and Pollux was 

 given to the fires that are often seen on vessels' masts 

 in storms, and which are electrical phenomena. Af- 

 ter their return, they released their sister Helen from 

 the confinement in which Theseus had for some time 

 held her. They were also among the heroes of the 

 Calydonian hunt. They wooed the daughters of Leu- 

 cippus, Phoebe and Ilaria, and were each obliged to 

 contend for their mistresses with their rivals, Idas 

 and Lynceus, the sons of Aphareus. Castor killed 

 Lynceus, and was slain by Idas. Pollux revenged 

 his brother's death by killing Idas ; but, full of grief 

 for the loss of Castor, he besought Jupiter either to 

 take away his life, or grant that his brother might 

 share his immortality. Jupiter listened to his re- 

 quest, and Pollux and his brother alternately des- 

 cended to Orcus and returned to life. It is doubtful 

 whether the ancients understood them as being toge- 

 ther or separate hi their alternate passage between 

 the upper and the lower worlds. The former opin- 

 ion seems to be the oldest ; he latter, to have gain- 

 ed ground subsequently. Temples and altars were 

 consecrated to them. In great perils, especially in 

 battles, th<; ancients believed that they frequently ap- 

 peared to mortals as two youths on white steeds, in 

 shining garments, with meteors over their heads : and 

 then they were chiefly called Dioscuri. They were 

 also represented side by side, either riding or stand- 

 ing, each holding a horse by the rein, with spears in 

 their hands and stars on their heads. In the heavens, 

 the Dioscuri appear as one of the twelve constella- 

 tions of the zodiac (the Twins). 



CASTOR-OIL. The castor-oil plant (ricintu pat- 



