A great chapter of the history of the world is written in the chalk. Few
passages in the history of man can be supported by such an overwhelming
mass of direct and indirect evidence as that which testifies to the
truth of the fragment of the history of the globe, which I hope to
enable you to read, with your own eyes, tonight.
Let me add, that few chapters of human history have a more profound
significance for ourselves. I weigh my words well when I assert, that
the man who should know the true history of the bit of chalk which every
carpenter carries about in his breeches-pocket, though ignorant of all
other history, is likely, if he will think his knowledge out to its
ultimate results, to have a truer, and therefore a better, conception
of this wonderful universe, and of man's relation to it, than the most
learned student who is deep-read in the records of humanity and ignorant
of those of Nature.
The language of the chalk is not hard to learn, not nearly so hard as
Latin, if you only want to get at the broad features of the story it has
to tell; and I propose that we now set to work to spell that story out
together.
We all know that if we "burn" chalk the result is quicklime. Chalk, in
fact, is a compound of carbonic acid gas, and lime, and when you make it
very hot the carbonic acid flies away and the lime is left.
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