It has always been difficult to determine the purity of silver in an object by visual means and many countries have tried to establish a system of ensuring that certain standards are kept to protect customers who buy silver objects.
In Britain our system developed about six hundred years ago, when laws were passed to fix the purity of silver in manufactured silver articles to be at least 925 parts of silver in every thousand parts.
These five nations have, historically, provided a wealth of information about a piece through their series of applied punches.
Originally this was a tax “for the encouragement of tillage”, but after 1806 when Irish silver was struck with the king’s head duty mark it became the mark signifying the Dublin Assay Office. The Hibernia mark was only introduced in 1730, and the monarch’s head mark came in in 1806, so we do not expect to see either.
Unlike the first photo, the marks are not in an orderly line. Clockwise from the top left we see the harp crowned (purity), the letter “h” (1727 in this case), and TW for the maker, Thomas Walker.
Fortunately, with the use of a single reference book, it is possible for even a complete novice to decipher the vast majority.
Although there are many books on the market which can be used to help read hallmarks, the standard book of reference, used by dealers and collectors world wide is Bradbury's Book of Hallmarks.
The metal is tested and marked at special offices, regulated by the government, known as assay offices.