Well, the idea was to portray this:
"Mercantilism is the economic theory that a nation's prosperity depended upon its supply of gold and silver, that the total volume of trade is unchangeable. Thus theory suggests that the government should play an active role in the economy by encouraging exports and discouraging imports, especially through the use of tariffs."
In the pic: green arrow encourage exports, red arrow discourage plus difference of value between gold and silver etc. it's a bit hazy pic I know.