146 



NA TURE 



[Dec. 16, 1886 



that, being in Blackburn to procure a marriage license, he 

 should be led to a secondhand bookstall in the market- 

 place to search for printed matter relating to his favourite 

 art. At a time when Mary Wolstenholme might properly 

 consider him as more anxious about the ns ajigusta doini, 

 he was engaged in negotiating the purchase of " The 

 Chemical Pocket-Book ; or. Memoranda Chemica, ar- 

 ranged in a Compendium of Chemistry, by James Parkin- 

 son, of Hoxton." This book, together with " The Tables 

 of New Nomenclature, proposed by Messrs. De Morveau 

 Lavoisier, Berthollet, and De Fourcroy, in 1787," opened 

 out a new world to him. He had, at the very outset of 

 his trials, convinced himself that it was only by a thorough 

 knowledge of the properties of dyeing materials, and of 

 their behaviour under varying conditions, that the opera- 

 tions of the dyer can be intelligently carried on : he now 

 saw that all this knowledge must primarily depend upon 

 chemical science, and that it was on chemistry that the 

 extension of his art must ultimately rest. This view of 

 the relations of science to practice strengthened with 

 Mercer's experience. Years afterwards, when he had 

 attained to fame, he was called upon to express his 

 opinion concerning the necessity of technical education 

 in this country. " I entirely concur with you," he wrote 

 to a friend, "that for the preservation and benefit of the 

 British arts and manufactures, the masters, managers, 

 and skilled artisans ought to be better instructed in the 

 rationale and scientific principles involved in their opera- 

 tions. Chaptal remarked that ' practice is better than 

 science ' {i.e. abstract principles), ' but when it is neces- 

 sary to solve a problem, to explain some phenomenon, or 

 to discover some error in the complicated details of an 

 operation, the mere artisan is at the end of his knowledge, 

 he is totally at a loss, and would derive the greatest 

 assistance from men of science.' Probably no person 

 would, from his own experience, confirm the above 

 remark, as regards the art of calico-printing, more 

 heartily than myself." He observed that, "as regards 

 good practical men, no district could excel Lancashire ; 

 but in all the processes, from the grey piece to the finished 

 print, embracing thirty to forty operations, both the 

 science and practical experience of the cleverest are 

 requisite to keep all things straight and to detect the 

 cause of, and rectify, mishaps. ... An amusing volume 

 might be written about ludicrous mistakes, and equally 

 ridiculous attempts to rectify them." 



Mercer's first important invention in calico-printing 

 was made in 1S17, and curiously enough it was in the 

 application of a colour akin to that which had fired his 

 ambition to become a dyer. He found in the alkaline 

 sulphantimoniates an excellent medium for procuring a 

 bright orange colour on cotton fabrics. Heretofore no 

 good orange suitable for the use of the calico-printer was 

 known. The best orange was made from a mixture of 

 quercitron yellow and madder red, but it was difficult to 

 adapt it to other colours in the styles then in demand. 

 Mercer's antimony orange supphed the want : it was not 

 only a fine colour in itself, but was capable of being com- 

 bined and interspersed in a great variety of styles. This 

 discovery led to his re-engagement at the Oakenshaw 

 Works : after a seven-years' service he was admitted as 

 a partner, having as a co-partner, for a while, Richard 

 Cobden; and he remained connected with the firm until 



its dissolution in 1S4S, when he retired from business with 

 a moderate fortune. 



It would be difficult in the space at our disposal to do 

 full justice to the many discoveries and improvements 

 which Mercer introduced into the art of dyeing and 

 printing. His skill and energy led not only to the inven- 

 tion of new styles and new colours, but to the development 

 even of new branches of chemical industry. His applica- 

 tion, for example, of chromium compounds practically 

 created the manufacture of bichrome : when Mercer first 

 began experimenting with this substance its cost was 

 half-a-guinea an ounce ; it is now produced by the 

 hundreds of tons, and may be b aught retail at less than 

 sixpence per pound. Some of his processes are, of course, 

 obsolete, but many are still in use : the " manganese 

 bronze," for example, which he introduced in 1823, seems 

 to re-appear about every ten years, and was in large 

 demand some three or four years since. Mercer was an 

 indefatigable experimenter: nothing is more extraordinary 

 than his skill and inventiveness in the application of his 

 new colours to the creation of fresh styles or novel 

 combinations ; his genius in this respect was almost 

 kaleidoscopic. 



One of the greatest improvements made by Mercer in 

 the operations of the dyer was his introduction of the 

 alkaline arseniates in what is called the " dunging " 

 operation, the object of which is to remove that portion 

 of the mordant which has not become insoluble and firmly 

 attached to the fabric by the process of " ageing." The 

 loosely-attached mordant, unless previously removed, 

 would dissolve in the dye-bath, to the injury of the whites 

 and the deterioration of the dyeing liquor. Of scarcely 

 less importance was his method of preparing mixed 

 cotton and woollen fabrics so as to enable the mixed 

 fibres to acquire colouring-matters with equal readiness. 

 His observation of the extraordinary facility with which 

 certain "lakes," or compounds of alumina with organic 

 colouring-matters, are dissolved by oxalate of ammonia 

 led to the introduction of a method of using aluminous 

 colour-precipitates in steam colour-work, which was ex- 

 tensively employed in the East Lancashire print-works. 

 And lastly, his method of preparing stannate of soda was 

 not only of service to the calico printer by greatly 

 cheapening an indispensable agent, but was of consider- 

 able pecuniary benefit to himself 



Mercer's skill and knowledge were ungrudgingly given 

 to the fellow-workers in his art, and he was constantly 

 appealed to by the calico-printers and chemical manu- 

 facturers of Lancashire for assistance and advice. His 

 acquaintance with the literature of the abstract chemistry 

 of his time was very remarkable. He had indeed all the 

 essential qualities and instincts of the scientific mind : 

 there was a certain comprehensiveness about the man, a 

 certain vigorous grasp of general principles, and a large- 

 ness of view which made his influence felt at once among 

 men of science. There is no question that had Mercer 

 devoted himself to pure science he would have attained 

 hardly less distinction than he has secured as a techno- 

 logist. His method of work was essentially scientific. 

 Thus no sooner did he become acquainted with the 

 doctrine of chemical equivalents than he had the 

 strengths of his chemicals and reagents adjusted to a 

 simple relation of their equivalents. Mercer indeed was 



