The Philosophy of the Weather. and a Guide to Its Changes

CHAPTER I.. Heat and Moisture Are Indispensable to the Fertillity of the

Heat and moisture are indispensable to the fertillity of the earth--Arrangements exist for their diffusion and distribution, and all the phenomena of the weather result from their operation--Heat furnished or produced mainly by the direct action of the sun's rays--Manner in which it is diffused over the earth--Other causes operate besides the sun's rays--The earth intensely heated in its interior--Heat derived from the great Oceanic currents, and the aerial currents which flow from the tropics to the poles, and from magnetism and electricity--Water distributed by an atmospheric machinery as extensive as the globe--Evidences of this--Its distribution over the continents of North America--Explanation of it--Source from whence our supply of water is derived, and from which our rivers return 1

CHAPTER II.. Our Rivers Return in the Form of Clouds, and in Storms and

Our rivers return in the form of clouds, and in storms and showers--Definition and character of storms--Differences in the character of the clouds which constitute them--Nomenclature of Howard--Its imperfections--New order of description--Low fog--High fog--Storm fog--Storm scud--N. W. scud--Cumulus-- Stratus--Cirrus--Compounds of the two latter--recapitulation in tabular form 24

CHAPTER III.. Our Rivers Do Not Return From the North Atlantic--All Storms and

Our rivers do not return from the North Atlantic--All storms and showers move from the westward to the eastward--Seeming clouds seen moving from the eastward to the westward are scud--They are incidents of the storm, and not a necessary part of it--The storm clouds are above them, moving to the eastward--Occasions when this may be seen--Admitted facts prove it--Investigations prove it--May be known from analogy--From the fact that there is an aerial current pursuing the same course in which the storms originate--Character of this current--Its influence upon our country--Importance of a knowledge of its origin, cause, and the reciprocal action between it and the earth--To this end necessary to go down "to the chambers of the South" 43

CHAPTER IV.. The Trade Wind Region--Its Extent and Arrangements--Its Belt of

The trade wind region--Its extent and arrangements--Its belt of daily rains and movable character--The trade winds--The extra tropical belt of rains--Connection between them and their annual movements--The counter-trades--Their origin and situation--One of them constitutes our aerial current--It originates in the South Atlantic as a surface-trade--Anomalies of the trade wind region--Dry seasons--Humboldt's description of them--Exist where the surface trades are situated--The rainless countries-- Concentrated counter-trade--Monsoons--Received theory in relation to them a fallacy--Cause of the great central phenomena-- Calorific theory a fallacy--Land not hotter under the belt of rains, nor sea materially so--Theory should be abandoned 52

CHAPTER V.. The Agent, Magnetism--Its Character and Currents--Oxygen

The agent, magnetism--Its character and currents--Oxygen magnetic--Precipitation at the belt of rains occasioned by depolarization--Storms originate in this central belt, and move toward the poles 82

CHAPTER VI.. Course and Functions of the Counter-Trade--Ours Come From the

Course and functions of the counter-trade--Ours come from the South Atlantic--Reason why it can not come from the Pacific-- Mistake of Mr. Redfield and Lieutenant Maury in regard to it-- All our storms originate in it--Proofs of this--State of the weather, whether hot or cold affected by it--Proofs of this--All our surface winds are incidents of it, and due to its conditions and attractions--Proofs of this--Character of the different winds--Anomalies of Mr. Blodgett accounted for--Received theory in regard to sea and land breezes a mistaken one--Proofs of this--Peculiar character of the N. W. wind--Identity with the winter Mexican northers--Character of the West India hurricanes-- Of the thunder-gust--Of the tornado--Sundry particulars in relation to the latter--Due to currents of electricity-- Proportions of winds in different localities--Examination of the work of Professor Coffin upon that subject--Examination of Lieutenant Maury's theory of the monsoons 92

CHAPTER VII.. Height of the Counter-Trade in Different Latitudes--Cause of the

Height of the counter-trade in different latitudes--Cause of the Calms of Cancer--Influence of mountains upon the counter-trade-- Reports of Herndon and Gibbon--Focus of precipitation in the extra-tropical belt north of its southern line--Evidences of this--The elevation of the counter-trade above the earth varies in the same latitude with the variations in the phenomena of the weather--Temperature of the counter-trade--Rain dust, its origin and indications--Volcanic ashes--How far they indicate its course of progression--Question whether there is an eastern progression of the body of the atmosphere above the machinery of distribution 179

CHAPTER VIII.. Important to Understand the Precise Character of the Reciprocal

Important to understand the precise character of the reciprocal action between the earth and the counter-trade--Connection between the width and movements of the belt of inter-tropical rains and the volume of the trades--Its peculiarities over Africa, the Atlantic, and South America--The magnetic equator-- Character of the storms which originate in the inter-tropical belt indicate local magnetic action--Supposed influence of volcanic action--Gulf Stream changes its position--This the result of magnetic action--Alternating contrasts of heat and cold, and rain and drought--Dr. Webster's history of the weather--Spots upon the sun--Their character and influence--Cold or warm periods during the same decade, and during different decades--Connection between the spots and magnetic disturbances and variations--Influence of the moon upon the weather--No decisive inference to be drawn from these facts, and a more critical examination necessary 204

CHAPTER IX.. Examination of Existing Theories--Calorific Theory the Prevailing

Examination of existing theories--Calorific theory the prevailing one--Lateral overflow of Professor Dove--Absurdity of his views in relation to them--His theory of hurricanes--Its absurdity--A new theory by Mr. Dobson--Three theories advanced by meteorologists of this country--Professor Espy's theory--Mr. Bassnett's theory--Mr. Redfield's theory--Extended examination of the latter--His theory in relation to the fall of the barometer contradictory in its character--Philosophy of the barometric change--No aid to be derived from these theories 232

CHAPTER X.. Further Inquiry in Relation to the Reciprocal Action Between the

Further inquiry in relation to the reciprocal action between the earth and the counter-trade--Terrestrial magnetism, and what we know of it--Its elements, and their variations--Their connection with the variations of atmospheric condition--Magnetism acts through its connection with electricity--Character of the latter and its variations--Their connection with atmospheric conditions-- Electricity as well as magnetism in excess over this country-- Effects of it upon our climate--Closer consideration of the atmospheric phenomena--Their diurnal changes and connections compared with those of magnetism and electricity--Grouping of all the diurnal variations--Particular and separate examination of them--Classification of storms--Examination in detail of the several classes and the primary influence of the earth or counter-trade in relation to each 285

CHAPTER XI.

Prognostics 340

THE PHILOSOPHY OF THE WEATHER.

CHAPTER I.

Heat and moisture are indispensable to the fertility of the earth. Without suitable arrangements for their diffusion and distribution, and within the limits of certain minima and maxima, it would not have been habitable, or the design of its Creator perfected. These arrangements therefore exist, and "while the earth remaineth seed time and harvest shall not cease." Few and simple in their character, though necessarily somewhat complicated and irregular in their operation, the ultimate result is always attained. A beautiful system of compensations supplies the losses of every apparent irregularity in one section or crop, by the abundance of others.

From the operation of these few, simple, connected, and intelligible arrangements for the diffusion of heat and the distribution of moisture over the earth, result all the phenomena which constitute the weather; and by studying them, and their operation, we may acquire an accurate knowledge of its "Philosophy."

The necessary heat is furnished, or produced, mainly by the direct action of the sun's rays; and the most obvious feature in the arrangements for its diffusion is that by which the sun is made to shine successively and alternately upon different portions of the earth. Nothing animate or organic could endure his burning rays, if they shone continuously or vertically upon one point, or could exist without their occasional presence. Hence the provision for a diurnal rotation, to prevent the exposure of any portion of the globe to the action of those rays for twenty-four consecutive hours, except for a limited period, and at a considerable angle, in the polar regions. But the earth is spheroidal, and a diurnal revolution would still leave that portion which lies under the equator too much, and the other too little, exposed to the action of the sun. This is obviated by an annual revolution of the earth around the sun, and an obliquity of its axis, by reason of which the northern and southern portions are alternately and, as far as the tropics vertically, exposed to the sun; and it is made to travel (so to speak) from tropic to tropic, producing summer and winter, and other important phenomena.

This obliquity and consequent change of exposure are in degree precisely what the wants of the earth would seem to require. If it was greater, the sun would travel further north and south, but the alternate winters would be longer and more severe. If it was less, the end would not be as perfectly attained.

The direct action of the sun's rays upon the earth, particularly those portions which lie north and south of the tropics, is not the only source from which the supply of heat is derived. Although there is a general increase of heat in spring and summer when the sun travels north, and of cold when he travels south in winter, yet there are frequent irregularities attending both. Very sudden and great changes occur in each of them. Frost sometimes, cool weather often, occurs in midsummer, and considerable heat and tornadoes in midwinter. And ordinarily the maxima and minima of each month and, indeed, of each week are widely apart. Even in the polar regions, in midwinter, where the sun does not shine at all, the same moderating changes with which we are conversant occur in degree. An extract or two from the register found in Dr. Kane's narrative of the "Grinnell Expedition" will illustrate this.

Continue reading The Philosophy of the Weather. and a Guide to Its Changes free in the Wunder reader →