I'm surprised nobody has pointed this out, which to me seems like the easiest illustration of what that author means.
According to this site [http://onlygold.com/m/Prices/Prices200Years.asp]
an ounce of gold cost $19.39 in 1807. I'm assuming that this price is not adjusted to 2017 dollars.
So if your great great grandpa decided to buy an ounce of gold, it would have cost him $19.39 at that time in 1807 dollars. Say puts that ounce of gold into a vault and you inherit it today. You have an ounce of gold worth $1235 in present day dollars.
So every dollar used to buy gold back in 1807 would have returned 1235/19.39 = $63.69.
( author probably wrote the article when gold today was worth a bit more)
According to this site [http://onlygold.com/m/Prices/Prices200Years.asp]
an ounce of gold cost $19.39 in 1807. I'm assuming that this price is not adjusted to 2017 dollars.
So if your great great grandpa decided to buy an ounce of gold, it would have cost him $19.39 at that time in 1807 dollars. Say puts that ounce of gold into a vault and you inherit it today. You have an ounce of gold worth $1235 in present day dollars.
So every dollar used to buy gold back in 1807 would have returned 1235/19.39 = $63.69.
( author probably wrote the article when gold today was worth a bit more)