1. This slide rule is used for cask gauging. It is of the form developed by Everard in the 17th century, i.e. it has scales on 4 sides.

2. Two of the faces are used for calculating the content of full barrels. The other two are used for ullaging, calculating the content of partly full barrels. These are shown below with the marks S.Ly and S.St,.

3. The rule was made by Dring and Fage whose address is given as 248 Tooley Street London. They were at this address from 1796 to 1804. This is consistent with the AG (Ale gauge) and WG (Wine gauge) gauge marks which disappeared after the introduction of the unified imperial gallon in 1824.

4. On the reverse of one of the slides are scales for "2nd Variety" and "Spheroid". These were corrections to applied for different shapes of barrel.

5. The backs of the slides have a lot of information, not all of which I at present understand (but I'm working on it.). One of marks is for cider (spelled cyder) or perry. Cider is a drink of a similar strength to beer and made from apples and Perry is the same but made from pears. Perry seems to have gone out favour but became the "in" drink" in the 1960s England.

6. For more information on this rule and how it was used see here.

Fourth face