Expert: Tom Novitski - 2/28/2011

Question
I own a set of weights and a scale made by P. Snell. Could you tell me if there is any significance in the weights being stamped with "PWt" instead of "DWT". I was told that the PWt is an earlier period usage of "penny weight" and "DWT" is later, is this so and what is the difference. Thankyou!

Answer
Pennyweight (dwt)
The pennyweight symbol is dwt. There are 24 grains in 1 dwt, and 20 dwt in one troy ounce. Because there were 12 troy ounces in the old troy pound, there would have been 240 pennyweights to the pound—the basis of the fact that the old British pound (currency) contained 240 pence. (However, prior to 1526, English pound sterling was based on the tower pound, which is 15⁄16 of a troy pound.) The d in dwt stands for denarius, the ancient Roman coin, referred to in the New Testament, that equates loosely to a penny. The symbol d for penny can be recognized in the old-style notation for British pennies, in which a quantity of money expressed in pounds, shillings, and pence was indicated using the symbols £, s, and d, respectively. For example, £6.11s.8d indicated six pounds, eleven shillings, and eight pence.

Hope that helps, tom