PLATE MARKS, or HALL MARKS. The legal impressions made in Great Britain on watch cases, jewelry, and gold and silver plate, after the material has been assayed at the various Govern ment assay offices. In the ease of jewelry the marks are, with a few exceptions, optional. There are four distinct kinds of plate marks: (1) the standard or quality mark, (2) the mark of a par ticular office at which the article was assayed, (3) the mark by which the (late of marking may be ascertained, and (4) the maker's private mark. Formerly if the article was dutiable the head of the reigning sovereign was also added, but in 1798 watch-cases were exempted front this rule, and in 1890 the practice was entirely abandoned. The standard mark of the London office is a lion passant for sterling silver; a crown with the figures 22 2 for 22-carat goldand the crown with the figures IS for 18-earat gold. Up to 1845 a lion passant was likewise the standard mark of 22-carat gold, and from 1697 to 1723, during which time the quality of stand ard silver was raised front .925 to .959, the standard mark was a lion's head, and the hall mark a figure of Britannia. The standard mark at Edinburgh is a thistle at Glasgow, a lion rampant at Dublin, a harp crowned with the figure 22 added in the case of gold.
The hall marks of some of the particular assay offices are: London, a leopard's head, crowned up to 1S23 : Edinburgh, a castle Glasgow, a tree, a fish, and a bell ; Dub lin, a figure of Hibernia 0; Chester, a sword between three wheat sheaves s Birmingham, an anchor In addition, the Sheffield office is designated by a crown ; Ex eter, by a castle with three towers: York, by five lions on a cross; and Newcastle, by three castles.
The date-marks of the Goldsmith's Hall, Lon don, which are changed annually on Slav 30th, are the first 20 letters of the alphabet, each series differing in some slight detail (either in the style of the letter or in the shape of the shield on which they are placed) from a former series. The date-marks of Birmingham, which are changed annually in July, are also letters of the alphabet.
The character of the maker's mark was op tional up to 1697, when it was fixed as the first three letters of his surname. Since 1739 the mark has been the initials of the maker's Chris tian name and surname. Watch-cases of foreign make when marked in Great Britain bear special stamps. In Switzerland there are various plate marks, hut the regulations concerning them are not comprehensive, and English marks are ac cepted in place of the Swiss.
BIBLIOGRAPHY. Consult: Britten, Watch and Bibliography. Consult: Britten, Watch and Clock-Makers' Handbook (London. 9th ed., 1896) ; Chaffer, Handbook to Hall Marks on Gold and Silrcr Plate (ib., 1595) Cripps, English Plate Marks (ib., 1852) ; id., Old English Plate (ib., 18S6).