OF THE MINERAL WORK.

is worth when collected by a concave mirror, or a well-polished metallic ring, or another instrument, and forced into a center. For a rightly prepared concave mirror having a diameter of only one span a unit of length, roughly nine inches ignites wood or another combustible body without any trouble. If the diameter is two spans, it melts Lead, Tin, Bismuth, and other easily liquefiable metals in the sun. Having 4 or 5 spans, it melts Copper and Silver, and softens Iron so that it can be beaten upon an anvil. If, therefore, this is demonstrated by experience itself, that a collection of rays gathered and forced into a point has such great powers—that is, to melt metals and to reduce to smoke Mercury, Antimony, Arsenic, Auripigment orpiment, Cobalt, and other volatile and immature metals of this kind—what do you think will happen if the rays of 10 or 20 fathoms are gathered? They would undoubtedly burn all metals, except for gold, like thread and elevate them into smoke. What are 10 or 20 fathoms if compared to the many thousands of miles that are attributed to the sun? If its heat (not to speak of other huge stars) is impinged into one place (which happens in the center of the earth), how incomprehensible do you think the heat is there? Nothing, indeed, will be so fixed that it can resist that fire, just as nothing in reality resists it, whence that point is necessarily empty, in which nothing can rest or remain.

You may object that I chatter much, but prove little