Steno, Hooke, and Burnet

Nicolaus Steno. The Prodromus.[1]

Let us consider Glossopetrae Melitenses [literally, “tongue-stones of Malta”]. Were these once the teeth of sharks? …And were other such bodies—similar to marine bodies, and found far from the sea—once produced in the sea?

Many other bodies [that bear such resemblances to living things] are also found among the rocks. If one should say that [tongue-stones] were produced by the earth, or by the force of a particular location, one must confess that all the rest were also produced by earth, or by such a force…

And so I saw the matter finally brought to the same point that any given solid naturally contained within a solid [e.g., a tongue-stone in a rock] must be examined in order to ascertain whether it was produced in the same place in which it is found. [We must investigate] the character not only of the place where [a body] is found, but also of the place where it was produced….

[Here is what I propose:]

A natural body is an aggregate of imperceptible particles…
A solid differs from a fluid in this way: in a fluid, the imperceptible particles are in constant motion, and mutually withdraw from one another, while in a solid, although the imperceptible particles may sometimes be in motion, they hardly ever withdraw from one another so long as that solid remains a solid and intact.
While a solid body is being produced, its particles are in motion from place to place.

These statements hold true in all cases, whether one considers matter as atoms, or particles changeable in a thousand ways, or the four elements, or whatsoever chemical elements may be assumed to suit the differences of opinion among chemists…

These bodies which the earth contains receive from the earth nothing except the place in which they are produced and the matter supplied to them in that place through their pores. These things, which are produced by Nature, receive the determination of their particles from the motion of a penetrating fluid…

In the case of those solids, whether of earth or rock, which completely enclose plants and their parts, bones and the shells of animals, these bodies had already become hard at the time when the earth and rock containing them was still fluid. That is, the earth and rock did not produce these enclosed bodies… [Indeed, the enclosed bodies existed long before the matter of the earth or rock took the shape of earth or rock.]

If a solid substance is in every way like another solid substance, [not only in its external appearance, but also in the inner arrangement of parts and particles], it will also be like it in the manner and place of production…

The strata of the earth, in place and manner of production, are very similar to the strata which can be found wherever muddy water settles in layers.

Bodies dug from the earth, and which are in every way like the parts of plants and animals, were produced in precisely the same manner and place as the parts of the plants and the animals were themselves produced…

Robert Hooke, Micrographia (1665).[2]

Observation XVII: Of Petrified wood and other Petrified bodies.

Of this sort of substance, I observed several pieces of very differing kinds…That which I more particular examin’d, was a piece about the bigness of a man’s hand, which seemed to have been a part of some large tree, that by rottenness had been broken off from it before it began to be petrified…This Petrified substance resembled Wood, in that:

First, all the parts of it seemed not at all dislocated, or altered from their natural Position, whilst they were Wood, but the whole piece retained the exact shape of Wood, having many of the conspicuous pores of wood still remaining pores, and showing a manifest difference visible enough between the grain of the Wood and that of the bark…

Next…, in that all the smaller and … Microscopical pores of it appear (both when the substance is cut and polished transversely and parallel to the pores of it) perfectly like the Microscopical pores of several kinds of Wood, especially like and equal to those of several sorts of rotten Wood which I have since observed…

It was differing from Wood:

First; in weight, being to common water as 3¼ to 1, whereas there are few of our English Woods, that when very dry are found to be full as heavy as water.

Secondly, in hardness, being very near as hard as a Flint; and in some places of it also resembling the grain of a Flint: and, like it, it would very readily cut Glass, and would not without difficulty, especially in some parts of it, be scratched by a black hard Flint. It would also as readily strike fire against a Steel or Flint, as any common Flint.

Thirdly, in the closeness of it, for though all the Microscopical pores of this petrified substance were very conspicuous in one position, yet by altering that position of the polished surface to the light, [one could see that the pores were not hollow].

Fourthly, in its incombustibleness, in that it would not burn in the fire; nay, though I kept it a good while red-hot in the flame of a Lamp, made very intense by the blast of a small Pipe, and a large Charcoal, yet it seemed not at all to have diminished its extension; but only I found it to have changed its color, and to appear of a more dark and dusky brown color…

Fifthly, in its dissolubleness; for putting some drops of distilled Vinegar upon the Stone, I found it presently to yield very many Bubbles, just like those which may be observed in spirit of Vinegar when it corrodes corals, though perhaps many of those small Bubbles might proceed from some small parcels of Air… driven out of the pores…

Sixthly, in its rigidness, and friability, being not at all flexible but brittle like a Flint, insomuch that I could with one knock of a Hammer break off a piece of it, and with a few more, reduce that into a pretty fine powder.

Seventhly, it seemed also very differing from Wood to the touch, feeling colder then Wood usually does, and much like other close stones and Minerals.

The Reasons of all which Phenomena seem to be:

That petrified Wood having lain in some place where it was well soaked with petrifying water (that is, such a water as is well impregnated with stony and earthy particles) [gradually somehow separated] stony particles from the permeating water, which stony particles, being by means of the fluid vehicle conveyed, not only into the Microscopical pores…. but also into the pores or interstitia… [They] thereby so augment the weight of the Wood, as to make it above three times heavier then water, and perhaps, six times as heavy as it was when Wood.

Next, they thereby so lock up and fetter the parts of the Wood, that the fire cannot easily make them fly away…

By this intrusion of the petrifying particles, this substance also becomes hard and friable; for the smaller pores of the Wood being perfectly wedged, and stuffed up with those stony

[1] Nicolaus Steno (1638-1686): Danish scientist. He published The Prodromus in 1669; he intended it as a preliminary work, as its full title reveals: A preliminary discourse [Prodromus] on a solid body contained naturally within a solid. The planned later work never appeared. This 1914 translation by John Garrett Winter has been extensively edited by LG.

[2] Robert Hooke (1635-1703): British scientist with omnivorous interests and talents. Find the original of this text at http://www.gutenberg.org/dirs/1/5/4/9/15491/15491-8.txt

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