This was waaaaaaaay back in the day when the penny was first struck in the eight century. Back then the penny was a silver coin that weighed one 240th of a pound. This is where the division of the pound came into play and this was the basis for hundreds of years after in the sense that there were 240 pence in a pound all the way until decimalization in 1971. So back in the day, 240 silver pennies actually weighed one pound. But of course over time the weight was changed and the metal was debased and so on. Throughout it's lifespan the pennies value inflated and it was debased and all of that and made smaller to the point where it wasn't an easy coin to use so in 1797 they introduced a much larger copper piece.
So if you have 10 silver florins or 20 silver shilling or 40 silver sixpence's and so on you will find that it will not equal one pound in weight because things have been changed oh so many times through out history.
The florin that you have that says "a tenth of a pound" is referring to its denomination and the pound currency, not the weight.
So if you have 10 silver florins or 20 silver shilling or 40 silver sixpence's and so on you will find that it will not equal one pound in weight because things have been changed oh so many times through out history.
The florin that you have that says "a tenth of a pound" is referring to its denomination and the pound currency, not the weight.




















