Socrates. These—the clouds—as they roll thunder.
Strepsiades. In what way, you all-daring man?
Socrates. When they are full of water, and are compelled to be borne along, being necessarily precipitated when full of rain, then they fall heavily upon each other, and burst, and clap.
Strepsiades. Who is it that compels them to be borne along? Is it not Jupiter?
Socrates. By no means, but ætherial vortex.
Strepsiades. It had escaped my notice that Jupiter did not exist, and that vortex now reigned in his stead. But you have taught me nothing, as yet, concerning the clap and the thunder."
But poetry and art were too strong in ancient Athens for such advanced ideas. Socrates was poisoned, and the artists reigned supreme for 1500 years.
Then our present knowledge of cloud-form and structure can be utilised to purposes of which the poets and painters never dreamt. Viñez has shown how the lie of the stripes of hairy cloud called "cocks'-tails " show the position of the dreaded vortex of a hurricane; and with this knowledge a sailor can not only save his ship from danger, but sometimes even utilise the cyclone to help him on his course. Mr. C. Ley has shown how the lie of similar cloud stripes indicate the approach of an ordinary British gale.
When we see a waterspout in the distance we do not think of a dragon and his tail, like the Chinese, but consider how to get out of its path or to break it up by firing guns. The whirlwind on the western prairies takes the specially intense form known as a tornado, and there the ingenuity of the American nation is exercised in the construction of tornado-proof houses.
But the research that has led to these important discoveries has incidentally involved a process which powerfully alters the attitude of mind induced by the personifying stage of mental development.
All research involves measurement. When a meteorologist sees an ominous mass of thundery cloud, he not only notes the direction in which the different layers are moving so as to gain some conception of the kind of vertical eddy that is associated with the storm, but he does more than this. He measures the height and thickness
