ROCKALL 



ROCKINGHAM 



755 



crust (aqueous, igneous, metamorphic, &c.) will 

 be found described under numerous distinct head- 

 ings in this work. See the classification given at 

 PETROGRAPHY, and the article GEOLOGY, with the 

 list appended, including such articles as DENUDA- 

 TION. See also BUILDING STONE, BLASTING, 

 BORING. 



Rockall (in old maps Rocol, Rochol, &c.), on 

 a deeply covered sandbank in the Atlantic 50 miles 

 long and 25 broad, in 57 36' N. lat., 13 42' W. 

 long., 160 miles W. of St Kilda, 290 from the 

 nearest point of the Scottish mainland, and 260 

 from the north of Ireland. It is an isolated conical 

 granitic rock on stratified masses, rising 70 feet 

 above the sea, and about 100 yards in circumfer- 

 ence. At a distance it looks like a ship in full sail, 

 the upper part being white with the dung of sea- 

 fowl, and the lower part dark stone. This curious 

 peak ia further from a mainland than any other 

 rock or islet of like size in any part of the world. 

 Martin, in his St Kilda (1698), mentions that a 

 crew of Frenchmen and Spaniards, shipwrecked at 

 Rockall in 1686, escaped in their pinnace to St 

 Kilda. The first landing known was in 1810. Ves- 

 sels come hither for cod -fishing from Scotland and 

 from Grimsby. 



See the account of a scientific expedition thither in 1896 

 in an article by Mr Miller Christy in the Royal Scottish 

 Geographical Magazine for 1898. 



Rock-basins, a name given by Sir Andrew 

 Ramsay to lacustrine hollows in rock which have 

 been excavated by glacier-ice. See LAKE. 



Rock-UUtter, an impure alum efflorescence 

 of a butter-like consistency found oozing from some 

 alum slates. 



Rock-crystal. See QUARTZ. 



Rocket is a cylindrical case of paper or metal 

 partially filled with an inflammable composition 

 (saltpetre 68 parts, sulphur 12 parts, charcoal, or 

 mealed powder, 32 part*), so that a large conical 

 hollow is left inside. The base is open or has 

 vents in it, and the head closed. On being ignited 

 this composition burning over the whole surface of 

 the hollow portion at once causes a great rush of 

 gas out of the base, thus driving the rocket for- 

 ward with great and increasing velocity. Rockets 

 are used for signalling and to carry a light line for 

 life-saving purposes ( see LIFE-SAVING APPARATUS ). 

 Early in the 19th century they began also to be 

 used' in war. Sir William Congreve in 1808 intro- 

 diioi-d iron war-rockets up to 24 Ib. in weight, with 

 thick iron heads adapted to act like a shell. They 

 were fired from a tube and steadied in their flight 

 by means of long sticks. In the more modern 

 Hale rocket a rotatory motion is given by causing 

 the gas to pass out of vents in the base bored 

 between three projecting shields, shaped somewhat 

 like the blades of a screw-propeller, against which 

 it presses. The cumbrous stick is therefore no 

 longer used, and the rocket is fired from a low 

 trough with tripod stand, or even from the ground, 

 by raising the head to the height necessary to give 

 the required range, which may be as much as 4000 

 yards. Though extremely portable as compared 

 with other missile weapons of similar power, 

 rocket* are so uncertain in their flight that they 

 re not much used, except for incendiary purposes 

 And against savages, who greatly dread them. 

 Against cavalry they would be very useful if they 

 con Id be depended on. The rocket troop of the 

 Royal Horse Artillery did very good service in the 

 Peninsular war, however, and ships' boats, which 

 could not carry a gun firing a 24-pounder shell, 

 can throw rockets of that weight into a place 

 under bombardment. See PYROTECHNY. 



Rocket, a name given to a number of plants of 

 the natural order Cruciferse, and belonging to the 



genera Brassica, Sisymbrium, Erysimum, Barbarea, 

 Hesperis, &c. Garden Rocket (Brassica Eruca, or 

 Eruca sativa) is an annual plant, a native of 

 Austria, with stem 2 feet high, upright and branch- 

 in" ; the leaves smooth, succulent, cut and toothed. 

 When in flower it has a strong, peculiar, and 

 disagreeable smell ; but when it is very young 

 this smell is almost imperceptible, and the leaves 

 are used as a salad, for which it is frequently 

 sown on the continent of Europe, and was formerly 

 cultivated also in Britain. The name Garden 

 Rocket is given also to Hesjieris matroncdis, also 

 called Dame's Violet (q.v. ), a favourite ornament of 

 our flower-borders. The Yellow Rocket of our 

 flower-borders is a double-flowered variety of Bar- 

 barea -oulgaris (see CRESS). The Wild Rocket 

 (Sisymbrium ojficinale, or Erysimum officinale) is 

 common in Britain, and is sometimes sown and 

 used as a spring potherb. 



Rock-fish. See WRASSE. 



Rockford, capital of Winnebago county, 

 Illinois, is on both sides of the Rock River, 86 

 miles by rail WNW. of Chicago. It is a well- 

 built town, with shady streets, and contains foun- 

 dries, flour, paper, cotton, and woollen mills, and 

 manufactures agricultural implements, carriages, 

 pumps, churns, furniture, cutlery, and plated ware, 

 boots and shoes, watches, soap, &c. Pop. ( 1880 ) 

 13,129 ; ( 1890)23,584 ; (1900) 31,051. 



Rockhilllinton, a town of Queensland, Aus- 

 tralia, situatedon the south bank of the Fitzroy, 

 35 miles from its mouth, and 420 NW. of Brisbane. 

 The town has wide streets, lined with trees, and 

 many substantial buildings, including the govern- 

 ment offices, hospital, and town-hall. It owes its 

 beginning ( 1858) to the extensive gold-fields in the 

 neighbourhood, the annual yield of which is valued 

 at 1,000,000 to 1,250,000; copper and silver are 

 also worked to some extent. The land around 

 is well adapted for grazing. The industries in- 

 clude tanning, sxiap and boot making, and meat- 

 preserving. The chief port for central Queensland, 

 its trade in exports (one-third) and imports reaches 

 an annual value of 1,500,000. A bridge across 

 the Fitzroy, with five spans of 232 feet each, con- 

 nects Rockhampton (pop. 7431) with its suburb 

 North Rockhampton (pop. 1700). 



Rockingham, CHARLES WATSON WENT- 

 WORTH, MARQUIS OF, a statesman of importance 

 beyond his abilities, was born in 1730, the only 

 son of that Thomas Watson Wentworth who 

 succeeded as sixth Lord Rockingham in 1746, and 

 was created marquis the same year. He had his 

 education at Eton, was created Earl of Malton in 

 the Irish peerage in 1750, and succeeded his father 

 as second Marquis of Rockingham in December 

 of the same year. In 1751 lie was nominated 

 lord-lieutenant of the North and West Ridings of 

 Yorkshire, and in 1760 made Knight of the Garter, 

 but soon found himself in opposition to the policy 

 of the young king George III. and his favourite 

 minister, Bute, and was dismissed from his lord- 

 lieutenancy in 1762. He found himself leader of 

 the combination of Whig opposition, after the 

 Duke of Devonshire's death in 1764, and in July 

 1765 was called on to form his first ministry. He 

 repealed the Stamp Act, and would have done 

 more for progress but for the secret intrigues of 

 the court, added to the defection of the Duke of 

 Grafton and his own want of influence in parlia- 

 ment. Rockingham resigned in August 1766, and 

 remained out of office sixteen years in opposition 

 to Lord North and the ruinous policy that lost 

 America. He again became premier in March 

 1782, with Fox and Shelburne as his secretaries, 

 but died 1 st July of the same year. See the Memoir* 

 by the Earl of Albemarle (2 vols. 1852). 



