I N D 



fman qnantlty can be put into the vefTel at once. Fig. s. 

 is an elevated feCtion of the fame mill. 



In tins machine the pulverization or granulation of the 

 indigo is cfFeftcd by the preffure of a nuiibcr of fmoctli 

 catt-iron balls, like thofe ufed for the (hot of great guns, 

 which, bein^ rolled among the indigo, prefs it into a pafte 

 by their weight, Kntil it unites with the liquid by which it 

 is \o he held in folution. 



InjSg. I, A rcprefents the bottom and rim of the vefP-1 

 which contains the indigo, and which is of a cylindrical 

 form. B is an upright fpindle, which, in this figure, docs 

 not appear. Upon the fpindle B is fixed a wheel C C, with 

 a convenient number of arms projecting round the vefTel, like 

 the radii of a circle ; and below each of thefe arms are pro- 

 je£ling pieces of iron, like the pins or teeth of a harrow, 

 for moving the balls. When this wheel C is moved round 

 its axis, the whole balls in the velTel A are fet in motion, 

 and, by rolling over the indigo, gradually prefs it, until it 

 unites with the water or liquid with which it is furrounded. 

 If the bottom of the cylinder be flat, a very fmall part of 

 the furface of each ball can acl upon the indigo ; but by 

 calling circular hollow grooves, as reprefented in Ji^. 2, 

 nearly the fenii-diameter of the ball will prefs upon the 

 iluff. The mill is moved by a handle I),Jg. 2, which fets 

 in motion the fmall bevel wheel E, and this wheel afting upon 

 the horizontal wheel F, fixed upon the fpindle B, fets it alfo 

 in motion, and confequently the wheel C C is moved round 

 its axis, a:id all the balls roll round upon the indigo. G is a 

 crofs .liaft upon the top of the fpindle B, loaded at each 

 end with a heavy ball. There is generally another fhaft 

 placed at right angles to this, when they aflill in regulating 

 and equalizing the motion in the fame manner as any other 

 fly wheel. When the indigo is found to be fufficiently dif- 

 folved, and united with the water, the liquid thus formed is 

 drawn off into any other veffei for ufe by means of a vent 

 and fpiggot placed in any convenient part of the bottom of 

 the velTel. 



Tlie great labour and time which it requires, and the 

 fmall quantity of ftuff which can be prepared at once by a 

 machine of this kind, renders it ill adapted for the ufe of 

 large works where much indigo is confumed, and where 

 they have generally a horfe-power water-wheel, or fteam- 

 cngine, for raifing water, cutting madder, and other pur- 

 pofes neceffary in extenfive works. Fig. 3. reprefents an 

 elerated crofs feclion of one of thefe machines, driven by 

 any moving power, and capable of preparing a very great 

 quantity of indigo at all times, as it requires no attendance, 

 excepting to empty the veflel when the indigo is wanted, 

 and add a frefli fupply. H is a femi-circular veflel of cait- 

 iron, placed upon a ilrong wooden frame O, and of any con- 

 venient length. I is a cover made in two pieces, with a cir- 

 cular aperture to admit the upright ftiaft K working upon 

 the centre, or pivot P. At Q, the upright P is jointed to a 

 horizontal fliaft uf wood M, the other end of which is con- 

 nected by the joint R, with a crank fixed on the end of a 

 horizontal fliaft N driven by the moving power. The cir- 

 cular motion of the fliaft and crank N communicates an 

 alternate, or reciprocating motion, by means of the horizontal 

 connecting fliaft M, to the upper end of the upright fliaft 

 K, which vibrating upon the centre joint P. fets in motion 

 the iron cylinders L, I>, in the body of the veflel, which 

 prefs upon the indigo, and produce tlie fame eflcft, but to 

 a much greater extent, as the balls in the machine firll 

 dtfcribed. The cylinders L, L, may be made of any dia- 

 meter or length which is found convenient. The greater 

 mafs of iron that they contain, the quicker and more effec- 

 tual will be tlicir operalion upon Uic llufF, provided there is 



IN B 



a fiifficient power to drive them. The frame under the 

 joint r extends the whole length of the femi-circular veflel H, 

 which may be any length, according to the e.x tent of the power 

 and quantity of work required. As thii machine requires 

 no attention whatever, it is found very ufeful in large dye 

 works, as, by means of it, they can conltantly command 

 a large fupply of prepared indigo, \^'hich may be drawn off 

 when wanted, for the longer it is under the preparing procefs, 

 the better in every refpecl, and frcfli indigo may be added 

 as the fupplv gets low. 



INDIGOFERA, in Bolany, yields the blue dye called 

 Indigo or Ir.dicum, fo eminently ufefiil in dyeing various 

 manufactures of a blue colour. This fubftance obtained the 

 name of indigo from its native country, India. — Linn. Gen. 

 ^^3. Schreb. 506. Willd. Sp. Pi', v. 3. 1220. Mart, 

 Mill. Diet. V. 2. Ait. Hort. Kcw. V. 3. 6;. Jufl". 359. 

 Lamarck Diet. V. 3. 244. Illuftr. t. 626. Gxrtn. t. 148. 

 Clafs and order, Dlade'iphia Decandria. Nat. Ord. PupiHo- 

 naceie, Linn. Legum'mofx, Jufl". 



Gen. Ch. Cal. Perianth of one leaf, fpreading, almoft 

 flat, five-toothed. Cor. papilionaceous ; itandard rounded, 

 reflexed, emarginate, fpreading ; wings oblong, obtufe, 

 fpreading at the lower margin, of the ftiape of the ilandard ; 

 keel obtufe, fpreading, deflexed, marked on each fide by an 

 hollow awl-fliaped point. Stam. Filaments in two bundles, 

 difpofed into a cylinder, afccnding at their tips ; anthers 

 fomewhat roundifli. Fiji. Genr.en cyhndrical ; flyle fliort, 

 afcending ; fligma obtufe. Fenc. Pod roundifli, long. 

 Seeds numerous, kidney-fliapcd. 



Efl". Ch. Caly.K fpreading. Keel of the corolla having 

 an awl-fhaped fpur on each fide ! Pod linear. 



Obf. Till within the lafl; century it was but imperfeftly 

 made out what plants produced the dye known to the 

 Romans by the name of Ind'icum. Mr. Miller, however, 

 cultivated the Iitd'igofera fo early as 1731 ; but he was ac- 

 quainted with only five fpecies of it ; w liich fame number 

 Linnreus imperfeftly defcribed. Profeffbr Martyn enume- 

 rates thirty-five fpecies, and Wiildenow fifty-one ; but fince 

 this genus is particularly known and eileemed for its uti- 

 lity in the arts, and that mod of its fpecies yield the blue 

 dye, as well as many other plants of the Aime natural 

 family, we fliall merely give a general outline of the genus, 

 without entering into a long fyllematic arrangement of the 

 fpecies. 



The genus /niAVo/J'riiiscompofedof flirubs and herbs, whofe 

 leaves are, in certain cafes, iimple, more generally ternate, 

 but moil frequently unequally pinnate. The leaflets in fome 

 fpecies are jointed and awned at the bafc. Stipulas diflinft 

 from the leaf-llalk. Peduncles axillary, generally many- 

 flowered, in fpikes or bunches. Many ipecies are natives of 

 the Cape of Good Hope ; for initaiice, I. fiUfoUa, fericta, 

 drprejfa, ovata, pforaloides, caitdicnns, amtctui, iiicana,procumbejis, 

 fiirmentofa, d^tiudala, frecia, coriacea, JUiform'u, tligiUita, Jrut 



Iefiens,jlrl3a, unguj/ifolia, and capillitris The rell are either 



from the Eall or Well Indies, Arabia Felix, New Holland, 

 and the coall of Guinea. 



It is faid that Pliny was aware that IiiJicum was a prepa- 

 ratiim from p. vegetable fubftance, though he was ill-informed 

 both coiKcrning the plant itfelf, and the procefs by which 

 it is made fit for ufe. The l<)llowing is a curious anecdote 

 to flifw that at the clofe of tlie i6th century it was unknown 

 in England what plant produced Indigo, for in a hook en- 

 titled '• Remembrances for Mafler S. by Richard Hakluyt," 

 written in 1582, Mailer S. is initruded "to know if Anile 

 that cslouivth blew, be a natural commodity of Turkey, and 

 if it be compounded of an herbe — to fend the feed or root 

 with the order of fowing, &c.— that it may become a natural 



commodity. 



