ARTIFICIAL FUEL. 



ARTIFICIAL LIMBS. 



manipulative nature are more beautiful in their remit* than the pro- 

 duction of artificial or imitative flower*. Nothing can well exceed the 

 faithfulness of theM imitation* ; rvery petal, leaf, ami bud U imitaUd 

 with an accuracy which must hare required long observation and much 

 ingenuity on the part of thoie who have practined thin art. 



The petal* of flowen are imitated by ribbon*, feathen, silk-worm 

 cocoons, cambric, taffeta, velvet, or thin laminic of whalebone shaped 

 and ooloured for the purpose. The stem* are mostly formed of wire*, 

 wrapped round with paper, rilk, or iw-.iu other material of the requisite 

 The leave* and petals are mostly cut and embossed by stamp- 

 ing with die* having (harp cutting edge*, and are united by mean* of 

 wire* and paste or cement. The mode* of colouring are various. Seed* 

 and similar object*, and small fruits, such as currants, are imitated by 

 wax, glass, and other substance*. Very beautiful imitations of some 

 plants are made with wax, rice-paper, and shells. Besides tha above 

 material*, flower* are occasionally imitated hi ebony, maple, box, satin- 

 wood, clove, nutmeg, pimento, jet, ivory, coral, pearl, sea-weed, and 

 hair. 



This manufacture is generally carried on in private houses, where a 

 large number of persons (mostly females) work together, each taking 

 certain department*, according to the principle of the division of 

 labour ; and the whole product is then sold to wholesale dealers, who 

 upply the retail shops. 



The French are especially distinguished in this art; all their delicacy 

 of taste is brought to bear upon it. France sells annually to the 

 extent of a million francs (40,000/.) to the foreigner; and England, with 

 the United States, purchases more than half this amount. 



We will take a rose, as a specimen of French imitative manufacture. 

 The petals, the leaves, the calyx, the buds, the stamens, the stalk all 

 require distinct .processes. First, for the petals. These ore made of 

 the finest cambric, which is cut out with punches, there being as many 

 different sized punches as there are different sizes in the petals of a rose. 

 Each petal, being held by pincers at the extreme end, is dipped into a 

 carmine dye ; then dipped into water to soften the tint at the edges ; 

 then touched with a brush to deepen the tint near the centre ; and any 

 little variegatod spots, or even blemishes, are imitated by tinting with 

 a brush. Next, for the leaves. These are made of Florence sarcenet, 

 which is dyed to the proper colour, and stretched while wet that it may 

 dry out perfectly smooth. The glazed surface of the leaf is imitated 

 by coating the sarcenet with thin gum-water ; while the velvety tex- 

 ture of the under surface is imitated either by a wash of coloured 

 starch-water or by a layer of flock or cloth powder, such as is used in 

 making flock paper-hangings. To imitate the ribs which form such a 

 peculiar and beautiful characteristic of the leaves, several leaves, placed 

 one upon another, are pressed between gaufroirs or goffering-irons, cut 

 with the required indentations. Then we have the leaflets which form 

 the calyx ; the sarcenet for these is stiffened with starch-water while 

 yet wet from the dyeing, and when dry the material is cut to the 

 proper size and shape by punches. The buds are made of sarcenet or 

 of kid, dyed or painted according to circumstances ; they are swelled 

 out to the proper shape by a stuffing of cotton, gummed flax, or crumb 

 <rf bread, and are tied with silk at the end of thin iron wires. The 

 stamens are made of silk, fixed at the ends of brass wires, and HO 

 shaped that the wire shall imitate the filament and the silk the anther; 

 the silk anther, being dipped into a glutinous liquid, is m-ule to retain 

 some very small seeds which imitate the pollen. I.a.-tly comes the 

 building-up nf the delicate structure : the stalk is made of iron 

 wire, coated with cotton and green paper, and an.mi<l this stalk 

 are grouped and fastened the several part* which together form the 

 imitative rose. 



ARTIFICIAL FUEL. Some of the compositions recently intro- 

 duced a* substitutes for coal will be noticed under FUEL. 



Al : T I K I ( I A 1 . 1 1 ( > I ! I ZOV is generally a cylindrical cup, about three 

 inches in diameter, or a rectangular trough, cither of tlu-m about half 

 an inch deep, and containing quicksilver. A circular plate of glass, 

 whose surfaces should be accurately jiorallel to one another, is laid on 

 the surface of the quicksilver in the cylindrical cup, but the trough is 

 usually covered by a roof with two inclined planes, each of which is a 

 frame carrying a plate of glass with parallel surface*. By these mean* 

 the wind I* prevented from agitating the fluid. 



The surface of the quicksilver being considered a* a plane perpendi- 

 cular to a diameter of the earth, or rather to a normal, at the place of 

 the observer, is parallel to the rational horizon of that place ; and con- 

 sequently the angle between the piano of the quicksilver and a visual 

 ray from the object to that iilanc, when corrected for refraction and 

 parallax, Is equal to the angular elevation of the object above the true 

 horizon <,( tho place. 



Artificial horizons of the kind ju*t mentioned are generally u*ed on 

 land for the purpose of obtaining the altitude of a celestial body by 

 means of an ocUnt. sextant, or reflecting circle, either held in the 

 hands or supported on a small pillar ; occasionally also it is employed 

 to obtain the angular elevation of a terrestrial object, as the top of a 

 tower, a mountain, Ac. The ray. of light from So object, falling on 

 the quicksilver, are reflected from thence to the eye of the observer; 

 and, by the law* of reflexion, the angles made with the reflecting 

 surface by the incident and reflected ray* an equal to on* another ; 

 hence the reflected image of the object appear* as much below the 

 horizon, or turface of the quicksilver, as the object itself is above it ; 



and on bringing, by the motion of the index of the sextant, the direct 

 and reflected image* to coincide, the angle read on the arc will, the 

 eye being very near the quicksilver, be equal to twice the angle of 

 elevation. 



In a regular observatory, the trough containing the quicksilver is, 

 sometimes, several feet long, in order to avoid as much a* possible the 

 necessity of changing its place according to the distance of the celestial 

 body from the zenith. 



When the atmosphere is very calm, water under a glass-roof u 

 used instead of quicksilver, but almost the least agitation <>f the air i- 

 sufficient to disturb the reflected image. 



On a journey, the conveyance of quicksilver 1* often inconvei 

 and therefore scientific travellers have attempted to use, as an an 

 horizon, a circular plate of polished metal, or a dark glans. 

 which light may be reflected as from a mirror. The horizontal ity 

 of Hiich an instrument is ascertained by means of a spiiv 

 placed upon it, and the adjustment is effected by three screws which 

 pan through the frame of the mirror at equal distances from one 

 another. 



Since, with the usual reflecting instrument .Ititudes ex- 



ceeding about 120 cannot be observed, the ftrtifiei.il horizon junt 

 described would be useless, if the altitude of the object were greater 

 than 60 ; they can however be employed with instruments similar to 

 those invented by Captains Fitzroy and Beechey, by which angles ex- 

 ceeding 180 may be observed. 



The artificial horizons permit very accurate observations to be made 

 on land, but it is evident that they cannot be used at sea, even though 

 well suspended in jimbals, on account of the unsteady motion of the 

 ship ; and some means of enabling a seaman to observe correctly the 

 altitudes of celestial bodies when the sea-line is invisible, or but faintly 

 seen through the vapours near the horizon, is still a desideratum. 



It is known however that when a conical or a cylindrical body, 

 terminating at the lower extremity in a point, is caused to i 

 rapidly on its axis, that axis soon takes, and for at least half an hour 

 maintains, a vertical position; and efforts have been made to employ 

 such a body, having a mirror on its upper surface, as an artificial 

 horizon on board a ship. A 'Nautical Top,' as it was rill, a, \va> 

 proposed by a Mr. Serson, and is described in the ' Philosophical 

 Transactions' for 1750 ; but, on being tried at sea, it irregularii 

 found to be great, and the contrivance was abandoned. The late Mr. 

 Troughton however, in 1818, made considerable improvements on the 

 original construction, but his success was not such as to render the 

 machine available. He made the top at first cylindrical, but he after- 

 wards gave it the form of a fruatrum of a cone; the redacting plane 

 formed the upper surface, and immediately under this was a stem 

 terminating below in a steel point, which rested on the concave surface 

 of a small steel cup. A rapid motion was communicated to the machine 

 by a series of wheels, of which the first was turned by means of a 

 handle on its circumference. 



The only contrivance which appears likely to serve the purpose of 

 an artificial horizon at sea is a spirit-level" appli.-d to the face of an 

 octant or sextant ; aud an instrument of this kind was proposed and 

 executed by Troughton. The spirit-level, in a brass tube, was placet! 

 between the index and horizon glasses; and, through a pei i.tr/itimi in 

 the tube, the observer could see in the horizon-glass the reflected image 

 of the bubble of air: a line was traced on the h onion-glass, 

 contact of the limb, or centre, of the celestial body was to oe made on 

 this line at the instant that the latter appeared to bisect the reflected 

 image of the bubble. The arc passed over by tho index would then 

 express the altitude of the celestial body above tho horizon. Instru- 

 ments very similar to this have been executed by Mr. Robinson, and, 

 for merely nautical observations, they posses* sufficient accuracy ; the 

 altitudes obtained with them being within two or three minute* of 



.AKTll'ICIAI. MM US, Ac. Considerable mechanical ingenuity i 

 di-play<l in supplying substitutes for limbs lil\ organs 



which :wcident or any other cause has rein 



The art of the dentist, for instance, calls for no small 

 mechanical skill. First, there is the choice of the ivory hi. I. 

 its colour, texture, and hardness, affords the best imitation "I Un- 

 natural teeth. Then there is tho shaping of tl the size and 

 form of tho tooth, whether single or <1" per or 

 under. And lastly there are the remarkable contrivances aided l.y 

 golden pnlati'S, springs, wires, cement, gutta percha, or other substances 



ity which tho tooth or mouthful of teeth are fixed in their place*. 

 Exjiorience teems to show that few kind.- of cheapness are so dear as 

 cheap tooth-making: so great are tin <liili< ulties in supplying teeth 

 that will readily eat their way through the difficulties presented to 

 tin ID. As for the succedaneums and metallic and other cements for 

 stopping decayed teeth, their merit depend* more ou the quality ! tie 

 material than on the mode of using. We see from time to time patents 

 for new contrivances in dental surgery, which involve no small an 

 of ingenuity. One such was enrolled by Mr. Diusdale, in whi< i 

 manufacture of teeth, palates, and gums is described ; and there arc 

 now many others. 



An artificial eye is an example of glass manufacture ; the shaping of 

 the glass being much less difficult than the accurate imitation of the 

 cornea aud iris by means of pigments and dye*. 



