It has been observed, and perhaps with a great deal of truth, that the arts which supply the luxuries, the conveniences, and the necessaries of life, have derived but little advantage in the first instance from the labours and speculations of philosophers; that the ingenuity of artists, the accidental or progressive discoveries of common workmen, in any particular branch of business, have frequently afforded _data_, from which, by the reasonings and investigations of philosophers, hints have sometimes been struck out for arriving at the same ends by a shorter way; that the learned are therefore more properly to be considered as improvers than inventors. Of this mortifying truth, the Chinese afford many strong examples in their arts and manufactures, and particularly in some of those operations that have a reference to chemistry, which cannot here be said to exist as a science, although several branches are in common practice as chemical arts. Without possessing any theory concerning the affinities of bodies, or attractions of cohesion or aggregation, they clarify the muddy waters of their rivers, for immediate use, by stirring them round with a piece of alum in a hollow bamboo; a simple operation which, experience has taught them, will cause the clayey particles to fall to the bottom: and having ascertained the fact, they have given themselves no further trouble to explain the phenomenon. In like manner, they are well acquainted with the effect of steam upon certain bodies that are immersed in it; that its heat is much greater than that of boiling water. Yet, although for ages they have been in the constant practice of confining it in close vessels, something like _Papin's digester_, for the purpose of softening horn, from which their thin, transparent, and capacious lanterns are made, they seem not to have discovered its extraordinary force when thus pent up; at least, they have never thought of applying that power to purposes which animal strength has not been adequate to effect. They extract from the three kingdoms of nature the most brilliant colours, which they have also acquired the art of preparing and mixing, so as to produce every intermediate tint; and, in their richest and most lively hues, they communicate these colours to silks, cottons, and paper; yet they have no theory on colours.