DYEING. 



Colouring 

 Maiun. 



Buccini 

 luund on the 

 American 



.iubstantite 

 colouring 

 matter pro- 

 cured from 

 ihcr ani- 



absorptioti of oxygen ; but Dr Bancroft, who has exa- 

 mined this subject very minutely, has ascertained that 

 the purple colour is produced without the access of air, 

 and that its formation is more probably owing to the 

 extrication of oxygen. I laving procured, in the month 

 of September IbOS, a Urge quantity of shell-fish, ap- 

 parently of the same specie* with those which Mr Cole 

 luul employed, mid agreeing in their specific characters 

 with the Luccinitm lapilliis of l.intKi-us, he made a great 

 number of experiments with the liquor which yielded 

 the purple colour, from which he found reason to con- 

 clude, that the presence of light was essentially neces- 

 sary to its production, and that the change of colour 

 was effected most speedily when the substances stained 

 with the liquor were exposed to the deoxidizing rays. 

 Some bits of muslin which he had stained with the 

 liquor, and preserved between the leaves of a book, re- 

 tained their original yellowish colour for nearly nine 

 years ; and on being exposedafter that time to the rays 

 of the sun, they were found as capable as ever of exhi- 

 biting all the changes of colour, and at last becoming 

 purple. 



65. A species of buccinum has also been found on 

 the coasts of Guayaquil and Guatemala in South Ame- 

 rica, which appears to have been long used by the na- 

 tives for dyeing or staining cotton. Don Antonio, Ulloa 

 describes them as larger than a nut, and containing a 

 mice, which, when expressed, is the true purple ; for, 

 he adds, if a thread of cotton, or the like, be dipped into 

 this liquor, it becomes of a mest vivid colour, which 

 repeated washings are so far from obliterating, that they 

 rather improve it ; nor does it fade by wearing. He 

 mentions also, that the purple colour does not appear 

 immediately, the juice being at first of a milky colour, 

 from which it changes to a green, and lastly to this ce- 

 1 ebrated purple. Ulloa, vol. i. p. 268. 



66. Catesby, in his account of the Bahama Islands, 

 (vol. i. p. 44.) mentions among the shells found there, 

 a species of buccinum which " yielded a purple liquor 

 like the murex, and which did not wash out of linen 

 stained with it. Josselyn also, in his New England Ra- 

 riliet Discovered" p. 37. says, at Paschataway, a plan- 

 tation about fifty leagues by sea eastward of Boston, in 

 a Miiall cove called Baker's Cove, they found this kind 

 of muscle, which hath a purple vein, which being prick- 

 ed with a needle, yieldeth a perfect purple or scarlet 

 juice, dyeing linen so that no washing will wear it out, 

 but keeps its lustre many years : we mark our hand- 

 kerchiefs and shirts with it." Mr John Nieuhoff also 

 relates, that " abundance of purple snails are found in 

 the islands over against Batavia." " They are boiled," 

 says he, " and eaten by the Chinese, who have a way 

 of polishing the shells, and pick out of the middle of 

 the snail a certain puqile-coloured substance , which 

 they use in colouring, and in making red ink. 



0'7. In addition to these, we may mention that Mr 

 Martin Lister ( P/iilosoph. Trans, vol. vi.) remarks, that 

 " the common hawthorn caterpillar will strike a purple 

 or carnation, with lye, and stand ; the heads of beetles 

 and pismires will, with lye, strike the same carnation co- 

 lour, and stand; and the amber-coloured scolopendra will 

 give, with lye, a most beautiful and pleasant amethys- 

 tine, and stand." In another part of the same volume, 

 Mr Lister mentions an insect cimcx, whose eggs, brui>ctl 

 upon white paper, " stain of themselves without any 

 addition of salt, of a lively vermilion colour." 



68. Dr Bancroft is of opinion, that the colouring juices 

 of some of these animals, particularly that of the bucci- 

 , might still be rendered beneficial in staining or 



printing fine muslins, for which but little colouring mat- 

 ter is required. No substance, he remarks, will afford a 

 substantive purple of equal beauty and durability, and 

 capable of being topically applied to linen and cotton, 

 with so much simplicity and expedition. But the dif- 

 ficulty of procuring and preserving the shell-fish, pre- 

 sent great obstacles to their ever being extensively em- 

 ployed for the purposes of dyeing ; particularly, as we 

 can obtain by other means, colours more beautiful, and 

 equally lasting. 



II. OfFegclablc Substantive Colourt. 



69. The substantive colours obtained from vegetables 

 are more numerous than those which are of animal ori- 

 gin, and far more interesting to the dyer. Of these, 

 the most singular, as well as the most important, is in- 

 digo, a blue colouring substance extracted from a genus 

 of plants known by the name of indigofera anil indigo, 

 which are cultivated for its production in America and 

 the West Indies. Indigo consists of a peculiar colour- 

 ing matter, which may be denominated its basis, and 

 which being combined with a certain portion of oxygen, 

 is, during its union, insoluble by any means unless 

 sucli as exert an agency more or less destructive on the 

 basis itself. This basis is, in its uncombined state, en- 

 tirely destitute of colour ; and seems to be formed by 

 certain peculiar secretory organs, possessed by a few 

 particular plants. Dr Bancroft states, that the expressed 

 juice of the leaves of the indigo plant communicate to 

 calico a greenish tinge, which in dyeing approaches to 

 blue, and ultimately assumes that colour ; and that re- 

 peated applications of it to the same spot, increase the 

 deepness of the shade, and at last produce a full blue. 

 He suspects, however, that the colouring matter of the 

 indigo, when thus applied in its native state, does not 

 absorb so much oxygen, as when it undergoes the fer- 

 mentive process by which it is usually prepared for the 

 purposes of dyeing. 



70. In another part of this work, (see INDIGO,) General 

 we shall describe the various processes which are properties, 

 employed for preparing indigo, and confine ourselves 



at present to a description of its nature and proper- 

 ties as a dye. In its prepared state, indigo is of a 

 very rich blue colour, which varies, however, in its 

 shade, in different specimens. Thla^difference seems 

 to be owing not so much to any real difference of qua- 

 lity in the colouring matter, as to the foreign substances 

 with which it is occasionally united. When indigo is 

 pure, it is light and friable; tasteless, and almost des- 

 titute of smell ; and having a smooth fracture. Some 

 varieties are lighter than water ; and the lightest is ge- 

 nerally the purest. Indigo is frequently adulterated by 

 adding to it gummy, resinous, and earthy substances, 

 particularly an extract from the fruit of the embryop- 

 teris glutinifera, denominated gaub in the F.ast Indies. 

 Both its weight and its purity are affected by the pre- 

 sence of lime, which having been used in excess, as a 

 precipitate, had subsided with the colouring matter, 

 and carried down other impurities along with it. 



71. The finest and most valuable indigo was formerly Diffi . rtBt 

 brought from Guatimala ; but since the manufacture of kiu(ls - 

 this commodity engaged the attention of the British digo. 

 inhabitants in 'the Kast Indies, indigo superior even to 



that of Guatimala has been imported, in considerable 

 quantity, from that quarter. J)r Bancroft enumerates 

 three varieties of American indigo: of which the first, 

 called by the Spaniards/ord, has a very fine blue colour ; 

 the second, which bears the name of iobrc salii'iilr, is vio- 

 let ; and the third, named corli-color, is copper-colour- 





