On A Piece Of Chalk

On A Piece Of Chalk by Thomas Henry Huxley

This summary has a great deal of information detailing how chalk shows us about the geological history of earths development. The summary contains excellent facts and scientific investigations.

Mr. Huxley originally gave the lecture "On a Piece of Chalk" in 1868 at a meeting of the British Association for the Advancement of Science to the working class of Norwich. His lecture served as a basis for other scientist who would modify or further explain the process of life development on earth. Loren Eiseley put forth great effort to revive interest in Huxley's essay which led to this presentation or it by mineral digest.

A very important part of the make up of earth's crust is chalk. One very large area of concentration of this element covers a great span in England, but is not limited to that area. Bands of the chalk are also found in Ireland, France, Denmark, Central Europe, North Africa, Crinea, Syria, and Central Asia. If all the bands were attached it would form a 3000 mile long irregular oval, the largest section would be that of England's, at 280 miles.

The reason chalk is so important is that it contains a great chapter of earth's history within its soft layers. As a number of different scientific tests show us, chalk is composed of carbonic acid and quicklime. The process by which these ingredients become chalk and its additional contents buried within are how chalk tells us the story of a time long past.

To the unassisted eye chalk appears to lock like a loose and open stone. Upon further investigation with a microscope chalk is formed from minute granules, embedded with a matrix of innumerable rounded bodies. Some are larger than others, but none of them are more than a hundredth of an inch in diameter. The majority of these look like badly grown raspberries called Globigerina. It is the study of these organisms