An electron is a subatomic particle with a negative electric charge that is equal, but opposite to, the positive charge of a proton.
Guinea (coin) The guinea was a coin of approximately one quarter ounce of gold that was minted in Great Britain between 1663 and 1814. The name came from the Guinea region in West Africa, where much of the gold used to make the coins originated. It was the first English machine-struck gold coin, originally worth one pound sterling, equal to twenty shillings, but rises in the price of gold relative to silver caused the value of the guinea to increase, at times to as high as thirty shillings. From 1717 to 1816,
Until 1971 (decimalization), a crown was 5 shillings. Then, between 1971 and 1990, it was worth 25 pence. Don't know if these older pieces, such as that Churchill crown, can still be exchanged into current money. The modern equivalent, in terms of weight and size, are the commemorative Â£5 coins ... Christian