After all the fertile land in the immediate neighbourhood of the first settlers were cultivated, if capital and population increased, more food would be required, and it could only be procured from land not so advantageously situated. – David Ricardo
Gold and silver, like other commodities, have an intrinsic value, which is not arbitrary, but is dependent on their scarcity, the quantity of labour bestowed in procuring them, and the value of the capital employed in the mines which produce them. – David Ricardo