splendour, must necessarily be identical (in nature) with that out of which they have their being: (they must be) earth, that is; (which earth itself is) plainly more glorious (than they), inasmuch as it is only after it has been tearfully wrought by penal labour in the deadly laboratories of accursed mines, and there left its name of "earth" in the fire behind it, that, as a fugitive from the mine, it passes from torments to ornaments, from punishments to embellishments, from ignominies to honours. But iron, and brass, and other the vilest material substances, enjoy a parity of condition (with silver and gold), both as to earthly origin and metallurgic operation; in order that, in the estimation of nature, the substance of gold and of silver may be judged not a whit more noble (than theirs). But if it is from the quality of utility that gold and silver derive their glory, why, iron and brass excel them; whose usefulness is so disposed (by the Creator), that they not only discharge functions of their own more numerous and more necessary to human affairs, but do also none the less serve the turn of gold and silver, by dint of their own powers,  in the service of juster causes. For not only are rings made of iron, but the memory of antiquity still preserves (the fame of) certain vessels for eating and drinking made out of brass. Let the insane plenteousness of gold and silver look to it, if it serves to make utensils even for foul purposes. At all events, neither is the field tilled by means of gold, nor the ship fastened together by the strength of silver. No mattock plunges a golden edge into the ground; no nail drives a silver point into planks. I leave unnoticed the fact that the needs of our whole life are dependent upon iron and brass; whereas those rich materials themselves, requiring both to be dug up out of mines, and needing a forging process in every use (to which they are put), are helpless without the laborious vigour of iron and brass. Already, therefore, we must judge whence it is that so high dignity accrues to gold and silver, since they get precedence over material substances which are not only cousin-german to them in point of origin, but more powerful in point of usefulness.
 Sæcularis.  De suo. Comp. de Bapt., c. xvii. sub fin.
 De suo. Comp. de Bapt., c. xvii. sub fin.