PREFACE.

xi

not the least fruitful; and producing daily, not barelynew applications of principles already known, but newfacts or principles to be further applied.

Having for several years employed myself at times inexperiments relative chiefly to the chemical arts, and madeproper dispositions for continuing such enquiries, I pub-lished in 1748 proposals for a very extensive work, con-sisting principally of those experiments, and of informationsreceived from workmen and others. The several articleswere to be printed in a miscellaneous manner, without re-gard to any one being connected with that which precededor followed it. As nothing was to be admitted but use-ful or interesting facts, it seemed of little importance inwhat order the facts should be disposed, provided, by meansof proper indexes, the reader could readily have recourseto such particulars as might occasionally be wanted.

Some friends advised an alteration in this plan, judgingit would be of more utility to the publick if the facts weremethodized; and the most convenient method was thoughtto be, to give a complete history of each art by itself in allits branches. The difficulty of such an attempt, and theimpossibility of executing it to any good purpose by onehand, were apparent: nor would a simple detail of themanual operations of different workmen be anywise agree-able, either to the views, or the materials, with which Ihad engaged in the undertaking.

Another way occurred of procuring some degree ofregularity, without departing from the original views, anyotherwise than by rendering them more comprehensive,

b Many