HOR 



ROT 



board, the heaving at the sledge could not 

 cause the strands immediately behind the 

 top to close well, without having previ- 

 ously produced an extravagant degree of 

 twist in the intermediate rope. The ef- 

 fort of the crank must therefore he as- 

 sisted by men stationed along the rope, 

 each furnished with a tool called a wool- 

 der. This is a stout oaken slick, about 

 three feet long, having a strap of soft 

 rope yarn, or cordage, fastened on its 

 middle or end. The strap is wrapped 

 round the laid rope, anil the workman 

 works with the stick as a lever, twisting 

 the rope round in the direction of the 

 crank's motion. The woolders should 

 keep their eye on the men at the crank, 

 and make their motion correspond with 

 theirs. Thus they send forward the twist 

 produced by the crank, without either in. 

 creasing or diminishing it, in that part of 

 the rope which lies between them and 

 the sledge. Such is the general and es- 

 sential process of rope-making. The fi- 

 bres of hemp are twisted into yarns, that 

 they may make a line of an, length, and 

 stick among each other with a force equal 

 to their own cohesion. The yarns art- made 

 into cords of permanent twist by laving 

 them ; and that we may have a rope of 

 any degree of strength, many yarns are 

 united in one strand, for the same reason 

 that many fibres were united in one yarn ; 

 and in the course of this process it is in 

 our power to give the rope a solidity and 

 hardness, which make it less penetrable 

 bv water, which would rot it in a short 

 uhiie. S>>nie of these purposes are in- 

 consistent with others ; and the skill of a 

 rope-maker lies in making the best com- 

 pensation, so that the rope may on the 

 whole be the best in point of strength, 

 jtiiitncy, and duration, that the quantity of 

 hemp in it can produce. The following 

 rule for judging of the weight which a 

 rope \vil bear is not far from the 

 truth. Jt supposes them rather too 

 strong; but it is so easily remember- 

 ed, that it may be of use. Multiply the 

 circumference in inches by itself, and 

 take the fifth part of the product, it will 

 express the tons which the rope will car- 

 ry. Thus, if the rope has six inches cir- 

 cumference, 6 times 6 is 36, the fifth of 

 which is 7 tons. 



5 



HOPE yam, among sailors, is the yarn 

 of any rope untwisted, but commonly 

 made up of junk; its use is to make sin- 

 net, mats, &,c. 



HOKIUULA, in botany, a genus of the 

 Pentandria Monogynia class and order. 



Essential character: calyx five-leaved; 

 corolla five-pet*! led ; a-u.hi.i-j, scroUtorm 

 at the base : cap-uie three-vj ived. There 

 is but out species. ;-?'c H. dendata, a ua 

 live of the Cape of Good 11 <pe. 



IIOS V, in botany, the rove, a genus of 

 the Ic-'sanclria Polygynia class and order. 

 Natural order of Senticosx. Ro.sacex, 

 Jussieu. C;iiyx pitcher-shaped, hve-cleft, 

 fleshy, contracted at the neck ; petals 

 five ; seeds very m my, hispid, fastened to 

 the ir.ner side of the calyx. There are 

 forty species. 



UOSAC1C add. During certain disea- 

 ses, the urine, when it cools, deposits a 

 peculiar substance, which has been deno- 

 minated, from its colour, which re-em- 

 bies bricks, luteritious sediment. During 

 fevers, this appearance ot the urine lakes 

 place ; and in gouty persons, at the ter- 

 mination of the paroxysms, it is very 

 abundant. And when this suddenly dis- 

 appears, and the urine at the same time 

 continues to deposit this substance, a re- 

 lapse may be dreaded. It appears :n the 

 form of red flakes, and adheres strongly 

 to the sides of the vessel If the urine be 

 heated, this sediment is again dissolved. 

 This substance was formerly considered 

 by chemists as the uric acid. If into fresh 

 urine, a little nitric acid is dropped, it 

 becomes muddy, and a precipitate is form- 

 ed. The nitric acid and the substance to 

 which the name of rosacic acid has been 

 given combine together, and are deposit- 

 ed. The uric acid being much, less solu- 

 ble than the rosacic acid, it is very easy 

 to separate them. All that is necessary- 

 is, to pour boiling water on the sediments, 

 and to wa^h them on the same filter, in 

 which case the uric acid remains behind. 



ROSMARLNLS, in botany, a genus of 

 the Diandria Monogynia class and order. 



Natural order of Yerticillatx. L-biatx, 

 Jussieu. Essential character : corolla un- 

 equal, with the upper-lip two-parted; 

 filaments long, curved, simple, with a 

 tooth. There are two species, viz. R. 

 ofTicimilis, officinal rosemary ; and R. chi- 

 lensis. Chili rosemary. 



ROTACEJS, in botany, the name of the 

 twentieth order in I.innseus's Fragments 

 of a Natural Method, consiting of plants 

 with one flat, wheel-shaped petal. Among 

 the genera of this order is the gentiana, 

 the root of which is a well-known stom- 

 achic, and makes u principal ingredient in 

 bitters. The plant grows plentifully in 

 the mountainous parts of Germany, from 

 whence the roots are brought to England 



