easy enough to bring past ages close to us.  The Chaldeans, building their great embankments or raiding upon Job’s herds, are no longer a myth to us when we remember that they were wet by the rain and anxious about the weather and their crops, just as we are; in fact, they felt such matters so keenly, and were so little able to cope with these unknown forces, that they made gods of them, and then, beyond prayers and sacrifices, troubled themselves no further about the matter.  Even the shrewd, observant Hebrews, living out of doors, a race of shepherds and herdsmen, never looked for any rational cause for wind or storm, but regarded them, if not as gods, as the messengers of God, subject to no rules.  It was He who at His will covered the heavens with clouds, who prepared rain, who cast forth hoar-frost like ashes:  the stormy wind fulfilled His word.  Men searched into the construction of their own minds, busied themselves with subtle philosophies, with arts and sciences, conquered the principles of Form and Color, and made not wholly unsuccessful efforts to solve the mystery of the sun and stars; but it was not until 340 B.C. that any notice was taken of the every-day matters of wind and heat and rain.

Aristotle, the Gradgrind of philosophers, first noted down the known facts on this subject in his work On Meteors.  His theories and deductions were necessarily erroneous, but he struck the foundation of all science, the collection of known facts.  Theophrastus, one of his pupils, made a compilation of prognostics concerning rain, wind and storm, and there investigation ceased for ages.  For nearly two thousand years the citizens of the world rose every morning to rejoice in fair weather or be wet by showers, to see their crops destroyed by frost or their ships by winds, and never made a single attempt to discover any scientific reason or rules in the matter—­apparently did not suspect that there was any cause or effect behind these daily occurrences.  They accounted for wind or rain as our grandfathers did for a sudden death, by the “visitation of God.”  In fact, Nature—­which is the expression of Law most inexorable and minute—­was the very last place where mankind looked to find law at all.

About two hundred and thirty years ago Torricelli discovered that the atmosphere, the space surrounding the earth, which seemed more intangible than a dream, had weight and substance, and invented the barometer, the tiny tube and drop of mercury by which it could be seized and held and weighed as accurately as a pound of lead.  As soon as this invisible air was proved to be matter, the whole force of scientific inquiry was directed toward it.  The thermometer, by which its heat or cold could be measured—­the hygrometer, which weighed, literally by a hair, its moisture or dryness—­were the results of the research of comparatively a few years.  Somewhat later came the curious instrument which measures its velocity.  As soon as it was thus made practicable