136 



EXTRACTS FROM EXHIBITION LECTURES. 



[1853. 



tlie income of a family of moilcrato means. Taking rich and 

 jioor togetliei', and estuuating the cost of washing at no more 

 than 3<J. per head weekly, tiie annual chaige of washing to the 

 metropolis alone is 1,535,060/., wliich is equal to abo-.t one- 

 twenty fifth of the whole cajjital invented in the cotton manu- 

 factures of the Unitetl Kingdom. Hard water usually contains 

 lime; and in washing that earth unites with the fatty acid of 

 soap, producing an insoluble body of no use as a detergent. For 

 eve.y 100 gallons of Thames water, 30 oz. of soap are thus 

 wasted, before a detergent lather is formed. In personal ablution 

 we economize this excessi\e waste by tlie uncomfoi'table practice, 

 univereally followed in London, of taking about an ounce of 

 water into the hands, and converting it into a lather, the water in 

 the basin being only emplo3ed to rinse tliii otY, instead of aiding 

 in the detergence. But in washing linen this ])lau cannot be 

 followed, every particle of the lime being I'emoved before the soap 

 Leconios useful; this, as a matter of economy, is frequently 

 accomplished by carbonate of soda, as being cheaper than soap. 

 The amount of soap and soda salt thus wasted in the metropolis 

 has been stated to be equal to the gross water rental. Hard 

 water, besides wasting soap, produces a greater tear and wear of 

 clothes. 



All these facts are well known to manufacturers; and hence 

 the care with which a water is selected before the seat of a manu- 

 factory is detei'mined. Why, then, should we not attend to our 

 domestic manufactures, considered trifling only because they are 

 carried on with a great division of labour, unseen in its aggregate ? 

 Yet these domestic manufactures are of more importance, econo- 

 micallj', than those carried on in laige and imposing factories. 



I wish I had time to refer, with sufficient detail, to the dis- 

 covery of Mercer, who has shown that the immereion of cotton in 

 soda or in sulphuric acid causes an equal contraction of the 

 fibres, thus producing the mechanical effect of a loom. If a very 

 fine calico, containing as much as 180 picks to the inch, be thus 

 treated, it coutr.icts to calico of 260 picks to the inch — a fineness 

 not yet attained by any mechanical contrivance. This calico, in 

 addition to its acquired fi leness, has also assumed powers which 

 enable it tj receix'e coloure superior to those assumed bj' ordinary 

 calico. Before leaving tliis important discovery of Mercer, I 

 should allude to one other by the same chemist. The French 

 calico-printers employ mousselines-de-laine consisting altogether 

 of wool; while in England we use a much cheaper fabric, con 

 sisting of wool and cotton. The coloure on this mixture .are, how- 

 ever, extremely meagre when compared with the former; but 

 Mercer has shown that the mixed fabric acquires the properties 

 of the other when it is ti-eated with a bath of chloride of lime. 

 Tliis, one of the greatest discoveries ever made in calico-printing, 

 has been of great value to this country. 



I cannot, however, .illude to all tlie triumphs of Chemistry in 

 calico-printing, an art which has grown with the growth of 

 Chemistry, and strengthened with its strength. The knowledge 

 of mordants and of coloui-s, and the other results of chemical dis- 

 coveries, are of every-day occurrence. Let us take one of the 

 la.st exam]ilos. Lapis lazuli, long celebrated for its beautiful blue, 

 a!ni 'st raiik.'il auioiig tlif pivcicus stones, and was sold ataprice 

 whirli pill ii quit. •.lilt ,.f 111., nsaeh of the calico-printer. But 



ch ■iiii>t~, as.-.Ttaiiiiiig its position by analysis, soon learned 



how to make it by synthesis. Artificial ultramarine is now 

 manufactured at three or four shillings ]iev pound. But when it 

 was maile, how was it to be fixed on cloth ? From its insolubility 

 its fixation was a real difficulty. Chemists suggested that the 

 ultramarine might be mixed with albumen, which, being coagu- 

 lated with heat, would retain tlie colour on the cloth to which it 

 was applied. Whole barrels of the dried white of eggs are now 

 to be seen nt calico-print works. Yet this is an expensi\ e process. 



Could common cheese not be substituted for the white of eggs ? 

 Cheese is soluble in ammonia; and the ultraniaiine, beingmixed 

 with this solution, is retained by the cheese, \ylien the ammonia 

 evaporates. Now, therefore, the ultramarine is fastened on by 

 cheese, made from the buttermilk of Scotland, and sold under the 

 name of lactariue. 



Stannate of soda is a salt largely used by calico printei-s. The 

 usual mode of preparing it was, (1), tin was reduced from its ore ; 

 (2), this tin was dissolved in muriatic acid ; (3), it was oxidized 

 by nitric acid or chlorine; (4), the o.xide thus formed was preci- 

 pitated and redissolved by soda, tliis bulky, aqueous solution 

 being furnished to calico-printers. Meicer simplified the process, 

 and obtained it in the solid state by two operations: (1), the tin 

 was obtained as before ; (2), this tin was fused with a mixture of 

 nitiate of soda and caustic soda, the former oxidizing it, and the 

 latter forming stannate of soda with the oxide thus formed. Young 

 showed in the exhibition a still further simplification. The com- 

 mon ore of tin is an oxide : why then was it necessary to reduce 

 it to the metallic state merely to oxidize it again ? He therefore 

 fused the ore at once with soda, the impurities remaining undis- 

 solved ; and the salt was made by one opei'ation. I quote this 

 instance as a remarkable example of the tendency of Chemistry 

 to simplify processes of manufacture. 



I might refer to the important discoveries of vellow and red 

 prussiate of potash, the formers of Prussian blue ; but this would 

 only be to cite one out of innumerable appliances. I jsrefer, 

 therefore, to finish this part of the subject, by alluding to the 

 resists and discharges used in calico-printing. In order to pre- 

 serve white patterns in the process of dyeing, the nationj of the 

 East, whence calico-printing originated, still employ the most 

 laborious mechanical de\ices, each white spot being covered with 

 sealing-wax, or by being tied n'p and protected from the dye. By 

 the aid of chemistry, we either discharge the colour on the cloth, 

 or we put upon it bodies which resist the action of the mordants 

 and prevent the colour attaching to that particular part. Acids 

 made from the lees of wine (tartaric acid) and from the lemcn 

 (citric acid) are now largely used in these operations, and hence 

 come the beautiful patterns we enjoy in our dresses. It was found 

 that, even when the whites were thus obtained, they became 

 soiled in washing otf the excess of mordants from the other parts 

 of the cloth; and the only mode of pre\"enting this was, to treat 

 the cloth with a bath of cowdung. Large dairies were conse- 

 quently necessary adjuncts of a calico-print work. Chemistry has 

 shown that the action of the manure is due to its phosphates; 

 and a mixture of phosphate of soda, phosphate of lime, aud size, 

 is now substituted for the filthy baths formerly indispensable. I 

 could spend hours in discoui¥;ing to you on the triumphs of 

 Chemistry in the dyeing of textile fabrics, whether of cotton, wool, 

 and .silk, or their mixtures; but I must content myself with these 

 few isolated examples, and pass on to other subjects. 



Leather. — The manufacture of leather has been less advanced 

 by the application of Chemical Science than any other of the 

 arts. If Simon, the tanner of Joppa, had been able to .send leather 

 to the Exhibition, no doubt he would have carried off a medal 

 for leather as good, and made exactl\' by the same process, as th.at 

 of our most eminent manufacturers of the present day. And yet 

 the science of leather production is better undei'stood now than 

 then ; but so many physical conditions are involved in the pro- 

 duction ot good leather, that scientific jirocesses have been unable 

 to satisfy them all. The lii.les, steeped in an infu.si( n of o.ak b.ark, 

 absorb tannin and are converted into leather. Good sole leather 

 takes about a year to tan, and even calf-skins consume a month 

 in the operation. Chemists have certainly indicated substitutes 

 ff)r bark, Cfvntaining a greater amount of tannin ; and these, as for 



