L O H 



L O H 



reqviire an immenfe power to aftuate them, and are generally 

 worked by water-wheels or by fteam-engines. A plan and ele- 

 vation of a rafping engine is given in Plate XXXI. J\lcchaiucs, 

 _^gs. I and 2, where A is an iron cog-wliecl, turned round 

 by the large cog-wheel of a water-mill or lleam-engine ; its 

 axis has an iron cyhnder B fixed upon it, and this has a 

 number of fteel bars or knives a fixed in its circumference. 

 The pieces of wood to be rafped arc placed in a ilrong 

 wooden trough, D D, in which an iron bar, E, Aides, and 

 forces tlie wood down to the cylinder, being moved by two 

 racks, F, F, turned by pinions on an axis, G. At one end of 

 this is a handle, g, and at the other a wheel, h, which is 

 turned by a pinion, i, at the extremity of a long fpindle, 

 H I, which is turned by a wheel, K, whofe teeth arc en- 

 gaged by threads of a worm or endlefs fcrew, /, cut on the 

 end of the main axis. By this means the pinions are eonllantly 

 turning round with a very flow motion, and advance the 

 wood towards the cylinder, which is at the fame time in 

 motion, and its rafps cut the wood into powder. A 

 feiSion of the rafp cylinder is fliewn m^g. 3, where the fame 

 letters are ufed. In this m is the groove in which tenants at 

 the ends of the bar, E, Hide. This bar has many large fpikcs 

 in it, which faften into the wood. At 11 is a Itrong iron plate 

 at the end of the trough, to defend it from wearing away 

 by the great prelTure of the wood down upon it. The wood 

 is kept dawn in the trough by the crofs-b<jr, L, ^g. 2, fixed 

 down over them. The iron cylinder, B, is call with 24 

 grooves in it lengthways, and in thefe are laid as many fteel 

 bars, Y, 7^, fg. 3, the feftion of which is X. The angle, 

 r, being ground to a (harp edge, and the fide, r s, cut with 

 teeth, as feen at Z, fo that the edge is ferrated, as fiievvn by 

 Y, the knives are held in their grooves by a ftrong hoop, n, 

 fig. 2, driven on the ends of tlie cylinder over the knives, 

 and they are wedged in fall by fmall iron wedges. When 

 the wood in the engine is all rafped, and it needs a frefh 

 iupply, the pinion, k, is difengaged from the wheel h, and 

 then the winch, g, being turned by a mar, the racks are 

 withdrawn. To difengage the pinion, k-, its bearing is fixed 

 \\\ a beam, O, which fwings on a hinge at the upper end, 

 and the lower end has a rod, p, jointed to it, which is en- 

 gaged by a catch, r, when the handle, /, at the extremity 

 of the rod, is moved away from the cylinder, fo as to en- 

 gage the pinion, /■, with its wheel, h. But on moving the 

 end of the rod towards the cylinder, it is relieved from the 

 catch, and the pinion is difengaged from the wheel ; and 

 to prevent the bar, E, going fo far as to endanger its teeth 

 meeting the rafps, a pin is fixed into a particular part of 

 one of the racks, f, which takes hold of the rod, p, when 

 It has got as far us intended, and removes the rod from the 

 catch, r, and then the rscks do not advance any farther 

 to the rafps. The wheel at R S, joining in the axes H and I, 

 is called a friftion box : it confifts of an iron box, R, fixed 

 on the end of the axis, I ; its cavity receives a conieal plug, 

 S, fitted upon the end of the other axis, H, and prelfed 

 into the box by a lever, T, loaded with a weight. By this 

 jneans, if the wood does not rafp away fo faft as the motion 

 of the racks wonld advance it, the cone, S, flips round in 

 the box, R, and allows for the difference of the movements, 

 which would otherwile break the machine. The cylinders 

 of ralping engines generally turn round from i^ to 20 

 times per minute, and will rednce a great quantity of wood 

 to a powder in a fhort time. Figs. 4 and 5 are two eleva- 

 tions of a ch'ipping engine : here A is part of a ftrong iron 

 axis, turned with a confiderable velocity by water or fteam: 

 upon the end is a fmall circular flanch, B, to which is bolted 

 a circular iron-plate, D, in which four knives are fixed, fo 

 that their edges project a very fmall quantity before the 



furface of the wheel in the manner of a plane iron. E is an 

 iron frame containing the bearing for tlie pivot of the wheel ; 

 it has a fmall trough, F, cait all in one piece with it. All 

 this iron work is fcrewed down to the wood framing, G G. 

 I'lic wood, H, is in this machine prefented to the knives in 

 the wheel by a man who holds it in the trough, and advances 

 it as the knives cut away the end. Thefe chips are cut 

 acrofs tlie grain but obliquely, as is evident from fg. 4 : they 

 are afterwards ground to a fine powder by a rolling ftone, 

 or runner upon edge. A large and heavy fly-wheel i.i ufually 

 fixed on the axis. A, of the chipping wheel to regulate its 

 movement. A method of reducing logwood has been lately 

 introduced by fawing it with a circular faw (fee Saw), which 

 cuts oft' a flake from the end of a piece of wood .\-, fo 

 that the jar of the faw fliatters the flake all into powder. 

 By this means, at every cut the faw cuts away as much wood 

 a.^ its tliicknefs in faw dull and the flake, which is as 

 much more, is reduced at the fame time, fo that all the 

 wood is reduced, tliough only one-half is cut, whereas, in 

 the ralping *ngine, every particle muft be cut by the ma- 

 chine. This improvement merits the attention of the woollen 

 manufafturcrs, whofe numerous logwood mills would be 

 much improved by the adoption of this method. 



LOHA, a town of Algiers ; 28 miles E. of El Callah. 



LOHARCANA, a town of Nepaul ; 10 miles S. of 

 Batgao. 



LOHARINAPAUL, a town of Nepaid ; 15 miles S, 

 of Catmandu. 



LOHAROO, a town of Hindooftan, in Dooab ; 10 

 miles N.W. of Pattiary. 



LOHE, a town of Auftria; 12 miles W.S.W. of 

 Crems. 



LOHEIA, a town of Arabia, in the province of Ye- 

 men, on the coaft of the Red fea, founded, aSout three cen- 

 turies ago, by a Mahometan faint, who built a hut on the 

 ftiore where the town now ftands, and fpent the reft of his 

 days there as a hermit. After his death, a " Kabbat," or 

 houfe of prayer, was erefted over his tomb, and it was after- 

 wards gradually embellilhed and endowed. Some devout 

 perfons reforted hither, and built huts for themfelves about 

 his tomb. The harbour of Macabra, a neighbourinjf town, 

 being about this time filled up, the inhabitan's who deferted 

 it fettled at Lolieia, and transferred the feat of government 

 to this place. The territory of Loheia is arid and barren ; 

 and the harbour is imJifTerent, fo that at ebb-tide, laden 

 boats cannot approach near it ; but, notwithftanding this 

 difadvantage, a confiderable trade in coffee, brought from 

 the neighbouring hills, is carried on in this town. The 

 coffee is not fo good as that which is procured by way of 

 Mocha and Hodeida from Beit el Fakih, but it is purchafed 

 on more reafonable terms, and the carriage to .lidda is lefa 

 expenfive. On this account feveral merchants from Cairo 

 rcfide at Loheia, and others annually refort hither for the 

 purchale of coffee. In this town are alfo 40 poor Banians, 

 who are employed in different trades. ■ Loheia has no walls, 

 but is defended by 12 towers garrifoned by foldiers, and 

 placed at equal diftances round it. The height of their 

 gates render it neceflary to afcend them by means of lad- 

 ders. It is but one of thefe towers that adaiits of being 

 defended by cannons. Thus expofed to the depredations 

 of the Arabs, the inhabitants have been fometimes reduced 

 to the receflity of lea-ving the town, and of taking refuge in 

 a fmall ifland, whither they carry wiih them their molt va- 

 luable effects. Several of the houfes in Loheia are built of 

 ftone; but they are generally hnts, conftrufted after the 

 Arabian fafliion ; the wa.Is confiiling of mud mixed with 

 dung, and the roof thatched with a lort of grafs which is- 



comn>o« 



