xn

PREFACE.

Many of the arts have natural and strong connectionswith one another; working upon the fame materials, forpurposes either different or nearly the fame; or producingsimilar effects upon different or similar subjects. Oneproperty of such materials, or the production of one effect,,may therefore influence several arts: a colour, which canbe easily fixed in animal and vegetable fibres, is equallyof benefit to the woollen dyer, the silk dyer, the dyer oflinen, and cotton thread, and the callico printer: a colour-which will bear fire, and unite with vitreous bodies infusion, concerns equally the glass maker, the enameller,and the 'painter on porcelain.

The discoveries and improvements made in one art,,and even its common processes, are generally little knownto those who are employed in another, so that the work-man can seldom avail himself of the advantages which hemight receive from the correlative arts, and an effect,wanting to the perfection of his own art may be actuallyproduced in another. Thus, though the dyer of linencloth, and of linen and cotton thread, wants means ofcommunicating to them a black dye that shall endurewearing, the callico printer fixes both on linen and on.cotton a black as durable as can be wished for.

To enquire therefore by experiment into the differentmeans of producing one effect, and trace it through allthe arts in which such an effect is required; to examinethe chemical properties of one subject-matter, and considerits uses and applications in all the arts in which it is con-cerned; to proceed in this manner with the capital effects,and materials, so far as my own experiments, and my op-portunities