LATE PROFESSOR OF CHEMISTRY AT THE ALDERSGATE COLLEGE OF LONDON: LONGMAN, BROWN, GREEN, AND LONGMANS, PATERNOSTER ROW. 1849. Whilst this TREATISE was still in sheets, Mr. Shute Barrington Moody,-a gentleman whose long residence in the West Indies renders his remarks on the Colonial Sugar Manufacture of great value,—did me the kindness to look over the pages, and append certain remarks. They will be seen in the form of footnotes, to which the name of "Moody" is attached. PREFACE. If we take a survey of the numerous branches of manufacture which are now so generally followed in civilized countries, it will be found that the most recondite and elaborate suggestions of the philosopher have been applied to the actual necessities of commercial utility with a remarkable amount of practical success. It will be found that results, which first originated in abstract thought, great inventive tact, or acute power of observation, have at length become developed into operations of commercial no less than scientific magnitude-operations in the accomplishment of which the reasoning powers of the philosopher have been superseded by the tactile instinct of the artisan; and this with less sacrifice of accuracy than any one unacquainted with the routine of manufactures on the large scale could have ventured to suspect. The whole theory of calico printing is but the theory of chemical tests-its whole practice but their application on a gigantic scale; and here, as in numerous other instances, the laboratory chemist who suggested, is at length surpassed in his art by the practical tact, the elaborate mechanism, and, B |