[To] explain the phenomena of the mineral kingdom ... systems are usually reduced to two classes, according as they refer to the origin of terrestria…

- John Playfair

The mind seemed to grow giddy by looking so far into the abyss of time.

- John Playfair

Every river appears to consist of a main trunk, fed from a variety of branches, each running in a valley proportional to its size, and all of them to…

- John Playfair

To trace the series of these revolutions, to explain their causes, and thus to connect together all the indications of change that are found in the m…

- John Playfair

Amid all the revolutions of the globe, the economy of Nature has been uniform, ... and her laws are the only things that have resisted the general mo…

- John Playfair

Thus we conclude, that the strata both primary and secondary, both those of ancient and those of more recent origin, have had their materials furnish…

- John Playfair

The Author of nature has not given laws to the universe, which, like the institutions of men, carry in themselves the elements of their own destructi…

- John Playfair