2 \ 2 



D Y E I N G. 



Saltt of tin 

 bat when 

 Irmst oxida- 



Tbe tin 

 should be 

 jure. 



And also the 

 muriatic 

 a* id. 



I'haptaTs 



fecta as a mordant. The proportions which hi- found to 

 answer the pin | were alnmt 1 I oimivs of tin 



in a mixture of two pounds of oil ,,f vitriol (of the 

 usual strength), with about three pound* of muriatic 

 ai id of tin- spivilic gravity of 1.17. The muriatic acid 



'loulil IK- first poured upon a large quantity of granu- 

 lated tin, in a capricious g! iss receiver, and tile oil of 



. itriol afterwards added slowly : and these acids being 

 mixed, rfiould be left to ^turate themselves with tin, 

 which they will do in a longer or a shorter time, accord- 

 ing to the temperature of the atmosphere, without any 

 artificial heat. The murio-sulphiite of tin, prepared 

 according to the above directions, is perfectly transpa- 

 rent and colourlc *s, and will probably remain so for 

 many years. It will produce fully twice as mucli ef- 

 fect as the dyers' spirit, or nitro-muriatic solution of 

 tin, at less than a third of tin- expence. It has also 

 the proj>ert^ of exalting the colours of all adjective 

 dyes, says Dr Bancroft, more than the dyers' spirit, 

 and fully as much as the tartrite of tin, without chan- 

 ging the natural crimson of cochineal towards the M 1- 

 ii hue; and therefore he concludes, after having 

 made a great number of experiments with it, " I think 

 myself warranted in strongly recommending; the murio- 

 Milphate of tin, for dyeing the Compound scarlet co- 

 lour from the cochineal and crimson, and quercitron 

 yellow." 



21". Some chemists pretend that the muriate of tin 

 answers the purposes of a mordant most efficaciously 

 when the metal is most highly oxidated ; but the expe- 

 riments of J)r Bancroft, and the results obtained by 

 the writer of this article, lead to the very opposite con- 

 clusion. Tlie experience of practical dyers is also at va- 

 riance with that opinion ; for it is well known, that 

 when the muriate of tin has l>een long kept, and thus 

 had time to absorb more oxygen, it acts less powerfully 

 in fixing and exalting colours. Constant observation 

 teaches them, that a less lively and agreeable colour is 

 obtained when the solution is made with rapidity, and 

 the disengagement of much vapour, than when it is 

 conducted slowly ; doubtless, because in the fonner 

 case the metal is more highly oxidated. On this ac- 

 count, fresh solutions made with ordinary caution, are 

 preferable to old ones, however carefully prepared. 



218. The tin employed in the preparation of the 

 mordants, which have for their bases the oxides of that 

 metal, should be of the utmost purity ; common tin 

 being frequently adulterated with copper and lead, each 

 of which is prejudicial to the colour. Malacca, and 

 good English tin, are reckoned the best ; though even 

 the latter generally contains a little copper in combina- 

 tion with it. The presence of iron and copper may 

 easily be detected, by pouring a little pmssiute of lime 

 into the solution : the precipitate is blue if iron be 



ut, and of a bronze colour if it contains copper. 



219. The muriatic acid should also be in the purest 

 state in which it can be procured. When it is uncon- 

 taininuud with foreign matter, it is perfectly limpid 

 and colourless ; but it is frequently of a light yellowish 

 appearance, owing chiefly, it is supposed, to the pre- 

 sence of a small quantity of iron derived from the sea- 

 salt, used in procuring the acid. It may be obtained 

 pure, by subjecting it to a second distillation, from a re- 

 tort connected with a range of Woulfe's bottles, a little 

 muriate of soda having been put with it into the retort, 

 and a gentle heat applied. 



220. Chaptal has recommended a method of forming 

 the muriate of tin, by causing the vapour of muriatic 

 acid, as it is disengaged from the muriate of soda, to 



pan through a succcs.sion of large receivers, containing Of Mor. 

 gninn! ited tin, with a little water, to absorb the acid. danu. 

 The he.it pnxluced by the absorption of the vapour is "~~Y~* I ~ 

 siiHieient to promote a solution of the metal without 

 the expenee of fuel. If the receiver-; be constructed 

 and adapted to each other, upon the principle-; of 

 Woulfe's apparatus, the process may, in this way, be 

 conducted with :t coii.-idcr.iblc .-.IUML i.f \pnce. . 

 loss will be- sustained by the e\ : pm-.itioii of the acid, or 

 of the tin in combination with it, which takes place to 

 .I considerable extent, according to the ordinary me- 

 thod of effect ing the solution. 



'I'll. The salts which have already fallen under con- Other mdN 

 federation, constitute the principal mordants used in dants. 

 dyeing, though several other substance-- are ocea-ional- 

 h < luploycd tor the same purj>ose. M. D'Aiuhniirm v , 

 of Rouen, has made much use of a solution of bismuth, 

 which had formerly been proposed by M. Fofie, of t be- 

 some city. One part of bismuth is dissolved in lour Nitrate of 

 parts of nitric acid ; the solution is afterwards intro- bismuth, 

 duced into a bath containing tartar, and into which is 

 poured, at the same time, a solution of .sea-salt. 1'cr- 

 thollet has shewn, that in whatever way this mordant 

 is prepared, there is always formed a precipitate by the 

 addition of water, which renders the colouring matter 

 of a brown colour. Chaptal made ii.-t of it in dyeing 

 cotton red, for which its author has proposed it ; but it 

 was not productive of a greater effect than water acidu- 

 lated with nitric acid. 



2'22. The oxide of arsenic is also employed as a mor- Arsenic, 

 dant in dyeing. Vogler appears to have used with ad- 

 vantage a solution of this oxide with potash, in dyeing 

 thread and cotton of a red colour. Afttr dissolving the 

 solution in two parts of water, lie added to it a satu- 

 rated solution of alum. The mixture is at first turbid 

 and gelatinous; but it recovers its transparency, by gra- 

 dually adding to it a solution of alum. Thread and 

 cotton immersed for U\ elve hours in this mordant, 

 on being washed and dried, assume, with madder, a 

 very deep colour. The sulphurets of arsenic, known 

 by the names of orpiment, realgar, sandarach, yellow 

 arsenic, red arsenic, c. are al.-o used in dyeing, parti- 

 cularly in the preparation of indigo. The sulphuret 

 of antimony may be substituted for that of arsenic ; 

 but it does not communicate to the colour the same 

 brightness. 



223. The corrosive sublimate is also used in dyeing. Corrosive 

 Wilson employed it in the composition of tin- aluiui- sublimatt. 

 nous mordant for printing linen, in the proportion of 

 one-eighth of the sugar of lead. It appears, by the 

 experiments of Vogler, that this salt renders the colour 



of madder darker and more durable. 



224. The oxides of lead have been used as mordants, Oxides of 

 but they tarnish the lustre of colours Yoglcr obtained lead. 



a beautiful black, by galling thread and cotton impreg- 

 nated with the salt of lead, putting them afterwards in 

 a solution of sulphate of copper, and boiling them in a 

 logwood bath. 



M!>. Some metallic oxides have so strong an affinity Oxide of 

 for the substances to which they are applied, that they iron. 

 remain pennanently fixed on them, and produce colours 

 which are almost indestructible. In treating of the 

 oxide of iron as H mineral substantive colouring matter, 

 we noticed the readiness with which it enters into com- 

 bination with stuffs, and the ca-y method of communi- 

 cating, by means of it, a buff colour to cotton. \\ c have 

 now to remark, that the same substance may also be 

 iiM-il as a mordant, to. produce, with different colouring 

 principles, violet, prune, and Him: colours. This oxide 





