On this date, Robert Plot, British vicar and professor of chemistry at Oxford University, was born. Although totally unaware of dinosaurs, Plot published in his book, The Natural History of Oxford-shire, being an essay towards the Natural History of England (1677), the first known description of fossil material that was later identified as dinosaurian (now known to be from the dinosaur Megalosaurus):
He initially thought that the specimen he had described was part of a leg bone of one of the war elephants that the Roman general, Plautius, supposedly brought with him when his legions invaded Britain in 72 C.E., but Plot soon realized this could not be the case. He finally settled on what, to us, is an even more bizarre suggestion:
Come we next to such [stones] as concern the … Members of the Body: Amongst which, I have one dug out of a quarry in the Parish of Cornwell, and given me by the ingenious Sir Thomas Pennyston, that has exactly the Figure of the lowermost part of the Thigh-Bone of a Man or at least of some other Animal, with capita Femoris inferiora, between which are the anterior … and the large posterior Sinus … : and a little above the Sinus, where it seems to have been broken off, shewing the marrow within of a shining Spar-like Substance of its true Colour and Figure, in the hollow of the Bone … In Compass near the capita Femoris, just two Foot, and at the top above the Sinus … about 15 inches: in weight, though representing so short a part of the Thigh-Bone, almost 20 pounds. [Plot, 1677, p. 132]
There happily came to Oxford while I was writing of this, a living Elephant to be shown publickly at the ACT, An. 1676, with whose Bones … I compared ours; and found those of the Elephant not only of a different Shape, but also incomparably different to ours, though the Beast were very young and not half grown. If then they are neither the Bones of Horses, Oxen, nor Elephants, as I am strongly persuaded they are not … It remains, that (notwithstanding their extravagant Magnitude) they must have been the bones of Men or Women: Nor doth any thing hinder but they may have been so, provided it be clearly made out, that there have been Men and Women of proportionable Stature in all Ages of the World, down even to our own Days. [Plot, 1677, p. 137]
Although Plot’s view may seem unsophisticated in light of what we now know about dinosaurs, Plot was doing good science in interpreting his observations on an unknown object by invoking information about similar objects which had been described or discussed in the literature of the time. His specimen was clearly part of a femur, or upper leg bone, of a terrestrial vertebrate. In suggesting that the bone came from a Roman war elephant, and later a human being, Plot made a rational interpretation based on knowledge available to him.
Although similarities between fossils and living organisms could clearly be perceived, it did not, to Plot, necessarily follow that the one had come from the other. According to the neoplatonic school of thought, the whole cosmos is a web of hidden affinities, made visible in the resemblances between Man and his external world, between the heavens and the Earth, and between living and non-living entities. Neoplatonists could therefore attribute organic resemblances to the action of a pervasive moulding force or “plastic virtue” that governed the growth of living organisms, but also operated within the Earth. For Plot, this “plastic virtue” was crystallization, which he felt capable of remarkable feats:
That Salts are the principal Ingredients of Stones, I think has so sufficiently been noted already, that to endeavour any further Evidence of the thing, would be actum agere in me, and loss of time to the Reader: And if of Stones in general, much rather sure of Formed Stones, it being the undoubted Prerogative of the Saline Principle to give Bodies their Figure, as well as Solidity and Duration: No other Principle that we yet know of naturally shooting into Figures, each peculiar to their own kind, but Salts; thus Nitre always shoots into Pyramids, Salt Marine into Cubes, Alum into Octo, and Sal Armoniac into Hexaedrums,and other mixt Salts into as mixt Figures. [Plot, 1677, p. 123]