A scientific classification of watches would resolve itself under the following heads:—

I. Early watches, prior to the invention and general adoption of the fusee, that is, from about 1500 to 1540. This period would be further subdivided into (a) those with movements entirely of steel; (b) the next stage, with plates and pinions of brass and the wheels and pinions of steel; and the latest stage, (c), in which the plates and wheels were brass and the pinions of steel, as at the present day.

II. Watches from about 1540 to 1640, all having fusees, and being made of every conceivable shape and size: octagonal, oval, cruciform, in the shape of a book, and so on. The cases were sometimes of crystal or bloodstone, and enamelled designs and chased gold work were predominant features.

III. Watches of the seventeenth century, from 1610 to 1675, at which date the pendulum spring was invented. These are mainly round in shape, according to the fashion about 1620, which superseded the ancient quaint forms. The cases, both of silver and gold, were richly enamelled, and moving calendars and astronomical details were frequently made.

IV. Late seventeenth and early eighteenth century watches. These would embrace the period from 1675 to 1720, after the invention of the pendulum spring.

V. The eighteenth century watch. This should include all the improvements, changes in decorative style, and other details bringing the watch up to the threshold of the nineteenth century and modernity.

We can only indicate the type of watch as falling under the various periods, and specimens of the leading types are illustrated (pp. [283], [287]).

The watches are numbered in the illustrations from one to ten, and can thus be easily identified by the reader.