This might work with gold as well as silver coins (arguably), works with bitcoin "tokens", but it doesn't work with fiat money. And not just because the majority of dollars (for example) exist only as digital money (that could still be accounted for somehow), but primarily because the amount of money printed or emitted by a central bank makes up only a small part of monetary equivalents or substitutes that flow through the economy. For example, credit money is created and destroyed by banks...
Are you sure that it is not you who doesn't quite understand economics?
I don't wanted to go in too much details, but in this regard "inflation" is not "inflation of money" but "inflation of a particular type of money"
E.G. if we talk about bitcoin we can measure the inflation (increase) of the number of bitcoin tokens
If we talk about gold, we can measure the quantity of gold available overground in monetary form (because non-monetary - jewels - has different value and uses)
Same for silver.
Same for USD (printed and electronics). In these case we have many types of measure Money Base, M1, M2, M3, etc. based on what we want measure and the definition of any of the previous).
But we can not measure the quantity of money "per se" because money is a property not a thing. Everything can be used as money, if it has the right features.
If gold appreciate too much to be used for everyday payments (E.G. the newspaper, the coffee, candies), silver start to be used as a substitute of gold for its own properties and take over the uses where gold it is too much difficult to use. This would cause an appreciation of silver over its current value (and price) so other metals (copper/nickel) could start to be used to allow very small transactions.
This happen because it is difficult and costly to make a gold coin small enough to be useful in small purchases (a tiny 1/10 ounce ~ 3g gold coin is worth more than 100$), a little less difficult is do the same for silver (the same 3g coin would be worth today 1,5$) and copper and nickel would be more versatile for small payments.
Bitcoin has not this problem because being immaterial can be divided with arbitrary precision.
But we can not measure with a single number gold + silver + bitcoin + other.... Because they are not the same thing.
You can make some equivalence, like 1 ounce of gold = 70 ounce of silver, but these are valid only in the moment they are done, because the ration between one and another always fluctuate depending the market demand and offer.