_MADAM,_
I am very ready to give you my opinion of those two questions you sent
me, whereof the first was, _Whether that, which is rare and subtil,
be not withal pure?_ To which I answer, That all rare bodies are not
subtil, nor pure, and that all which is dense is not gross and dull:
As for example, Puddle-water, or also clear water, is rarer then
Quicksilver, and yet not so subtil and pure as Quicksilver; the like of
Gold; for Quicksilver and Gold may be rarified to a transparentness,
and yet be so dense, as not to be easily dissolved; and Quicksilver is
very subtil and searching, so as to be able to force other bodies to
divide as well as it can divide and compose its own parts. Wherefore my
opinion is, that the purest and subtilest degree of matter in nature,
is that degree of matter which can dilate and contract, compose and
divide into any figure by corporeal self-motion. Your second question
was, _Why a man's hand cannot break a little hard body, as a little
nail, whereas yet it is bigger then the nail?_ I answer, It is not
because the hand is softer then the nail, for one hard body will not
break suddenly another hard body, and a man may easily break an iron
nail with his hand, as I have bin informed; but it is some kind of
motion which can easier do it, then another: for I have seen a strong
cord wound about both a man's hands, who pulled his hands as hard and
strongly asunder as he could, and yet was not able to break it; when
as a Youth taking the same cord, and winding it about his hands as the
former did, immediately broke it; the cause was, that he did it with
another kind of motion or pulling, then the other did, which though he
used as much force and strength, as he was able, yet could not break
it, when the boy did break it with the greatest ease, and turning onely
his hands a little, which shews, that many things may be done by a
slight of motion, which otherwise a great strength and force cannot do.
This is my answer and opinion concerning your proposed questions; if
you have any more, I shall be ready to obey you, as,
Madam,
_Your faithful Friend_
_and humble Servant._