Page:Supplement to the fourth, fifth, and sixth editions of the Encyclopaedia Britannica - with preliminary dissertations on the history of the sciences - illustrated by engravings (IA gri 33125011196181).pdf/21

Rh While the fifth edition was in progress, the work fortunately became the property of its present owners. The formation of an Encyclopædia suitable in all respects to the knowledge, taste, and attainments of the age, and therefore to be composed by men of known acquirements in the various branches of Science and Literature, had been long meditated by Mr Constable; and it was in this spirit that, after becoming the principal proprietor of the Encyclopædia Britannica, he conceived the design of a Supplement, of such extent as to afford scope for large additions and improvements; and of such a complexion, as should recommend it to the general attention and assistance of the Literary world. This latter object was happily aided by the co-operation of two illustrious Philosophers; who, duly appretiating the utility of the undertaking, and the liberal and enlightened spirit in which it was conceived, agreed to contribute jointly an Historical Account of the progress of the Sciences, calculated both to supply a desideratum in our domestic literature, and to form a fit Introduction for such a work.

The charge of superintending this Supplement having been committed to the present Editor, it became necessary for him, to subject the extensive publication to which it was to be appended, with the contents of which he had previously but little acquaintance, to an accurate examination throughout. He is happy to acknowledge, that he was materially assisted in this laborious survey by an eminent friend, whose profound knowledge in the mathematical and physical sciences rendered his observations of the greatest value; and whose contributions, in these departments of the present work, display the same originality, ingenuity, vigour of thinking, and extent of information by which his name is so much distinguished in the annals of Science.

A difficult and embarrassing task remained to be performed, after the labour of this survey was surmounted. The omissions with which the fourth edition of the Encyclopædia was originally chargeable, presented a long list of particulars and topics that might be made the subjects of articles and treatises; the subsequent progress of discovery, of inquiry, and of events, furnished another; and it was necessary to make a selection from the whole;—determining, at the same time, in what cases subjects already treated were to be considered anew, and the proper form of the additions, in those cases where the defects were such as might be supplied in that way. In making these selections and adjustments, there were vari-