Elements

According to Timothy Leary, Mendelev devised the Periodic Table of Chemical Elements in 1868. (The Game of Life, pages 11-15.)

I hypothesize that Mendel had some idea about, say, the size of atoms, when he undertook his analysis. What was science saying about that at the time, and who was saying it?

From school days, I remember that one of the Greeks hypothesized the existence of atoms. As the story went, he suggested the existence of some part of things that cannot be further divided. Is that really what he asserted? It seems a bit counterintuitive.

But, how might the philosopher have arrived at his conclusion? Here's my reasoning: Consider something like a crumbly stone. It is a single object, that is clearly composed of numerous smaller objects. The texture of one of those smaller objects is similar to the texture of the stone ... in fact, we might be able to see some of those smaller objects crumbling into still smaller objects - grains. And those smaller objects, in turn, have, again, a texture that is similar to the texture of the whole stone, in terms, say, of hardness ... and also in terms of granularity. We might be able to see - visual inspection - hints of granular patterns in a grain of sand ... and a grain of sand might even be crumbling into still smaller particles - powder.

Beyond this, simple visual detection provides limited or little information. We are left to surmise that a grain of powder subdivides in turn into something we cannot readily detect. Is that an atom?

Returning to the question of what the philosopher meant by his idea of the atom, it seems more logical, to me, to think it was such a next step in size. Or, did he have extra information. It does appear (based on more modern information) that atoms indeed are quite hard to divide. Are they harder to divide than, say, rocks? Some rocks are quite tenacious.