The Philosophy of the Weather Part 23

"26th. Hazy morning (S. E.), cloudy; noon, a heavy, windy-looking bank in north (S. fresh), with dense cirrus fringe above, on its upper edge; clear in S.

"27th. Clear, warm (W.); bank in north; noon bank covered all the northern sky, and fresh breeze; 10 P.M., a few flashes to the northward.

"28th. Uniform dense cirro-stratus (S. fresh); noon showers all round; 2 P.M., a heavy squall of wind, with thunder and rain (S. W.

to N. W.); 8 P.M., a line of heavy c.u.muli in south; 8.30 P.M., a very bright and high c.u.mulus in S. W., protruding through a layer of dark stratus; 8.50 P.M., the cloud bearing E. by S., with three rays of electric light.

"29th. A stationary stratus over all (S. W. light); clear at night, but distant lightning in S.

"30th. Stratus clouds (N. E. almost calm); 8 A.M., raining gently; 3 P.M., stratus pa.s.sing off to S.; 8 P.M., clear, pleasant.

"_July_ 1st. Fine and clear; 8 A.M., cirrus in sheets, curls, wisps, and gauzy wreaths, with patches beneath of darker shade, all nearly motionless; close and warm (N. E.); a long, low bank of haze in S., with one large c.u.mulus in S. W., but very distant.

"2d. At 5 A.M., overcast generally, with hazy clouds and fog of prismatic shades, chiefly greenish-yellow; 7 A.M. (S. S. E.

freshening), thick in W.; 8 A.M. (S. fresh), much cirrus, thick and gloomy; 9 A.M., a clap of thunder, and clouds hurrying to N.; a reddish haze all around; at noon the margin of a line of yellowish-red c.u.muli just visible above a gloomy-looking bank of haze in N. N. W. (S. very fresh); warm, 86; more c.u.muli in N. W.; the whole line of c.u.muli N. are separated from the clouds south by a clearer s.p.a.ce. These clouds are borne rapidly past the zenith, but never get into the clear s.p.a.ce--they seem to melt or to be turned off N. E. The c.u.muli in N. and N. W., slowly spreading E. and S.; 3 P.M., the bank hidden by small c.u.muli; 4 P.M., very thick in north, magnificent c.u.muli visible sometimes through the breaks, and beyond them a dark, watery back-ground (S. strong); 4.30 P.M., wind round to N. W. in a severe squall; 5 P.M., heavy rain, with thunder, etc.--all this time there is a bright sky in the south visible through the rain 15 high; 7 P.M., clearing (S. W. mod.).

"3d. Very fine and clear (N. W.); noon, a line of large c.u.muli in N., and dark lines of stratus below, the c.u.muli moving eastward; 6 P.M., their alt.i.tude 2 40'. Velocity, 1 per minute; 9 P.M., much lightning in the bank north.

"4th. 6 A.M., a line of small c.u.mulo-stratus, extending east and west, with a clear horizon north and south 10 high. This band seems to have been thrown off by the central yesterday, as it moves slowly south, preserving its parallelism, although the clouds composing it move eastward. Fine and cool all day (N. W. mod.)--lightning in N.

"5th. Cloudy (N. almost calm), thick in E., clear in W.; same all day.

"6th. Fine and clear (E. light); small c.u.muli at noon; clear night.

"7th. Warm (S. E. light); cirrus bank N. W.; noon (S.) thickening in N.; 6 P.M., hazy but fine; 8 P.M., lightning in N.; 10 P.M., the lightning shows a heavy line of c.u.muli along the northern horizon; calm and very dark, and incessant lightning in N.

"8th. Last night after midnight commencing raining, slowly and steadily, but leaving a line of lighter sky south; much lightning all night, but little thunder.

"8th. 6 A.M., very low scud (500 feet high) driving south, still calm below (N. light); 10 A.M., clearing a little; a bank north, with cirrus spreading south; same all day; 9 P.M., wind freshening (N.

stormy); heavy c.u.muli visible in S.; 10.30 P.M., quite clear, but a dense watery haze obscuring the stars; 12 P.M., again overcast; much lightning in S. and N. W.

"9th. Last night (2 A.M. of 9th) squall from N. W. very black; 4 A.M., still raining and blowing hard, the sky a perfect blaze, but very few flashes reach the ground; 7 A.M., raining hard; 8 A.M. (N.

W. strong); a constant roll of thunder; noon (N. E.); 2 P.M. (N.); 4 P.M., clearing; 8 P.M., a line of heavy c.u.muli in S., but clear in N.

W., N., and N. E.

"10th. 3 A.M., Overcast, and much lightning in south (N. mod.); 7 A.M., clear except in south; 6 P.M. (E.); 10 P.M., lightning south; 11 P.M., auroral rays long, but faint, converging to a point between Epsilon Virginis and Denebola, in west; low down in west, thick with haze; on the north the rays converged to a point still lower; lightning still visible in south. This is an aurora in the west.

"11th. Fine, clear morning (N. E.); same all day; no lightning visible to-night, but a bank of clouds low down in south, 2 high, and streaks of dark stratus below the upper margin.

"12th. Fine and clear (N. E.); noon, a well-defined arch in S. W., rising slowly; the bank yellowish, with prismatic shades of greenish-yellow on its borders. This is the O. A. At 6 P.M., the bank spreading to the northward. At 9 P.M., thick bank of haze in north, with bright auroral margin; one heavy pyramid of light pa.s.sed through Ca.s.siopeia, traveling _westward_ 1-1/2 per minute. This moves to the other side of the pole, but not more inclined toward it than is due to prospective, if the shaft is very long; 11.10 P.M., saw a ma.s.s of light more diffuse due east, reaching to _Markab_, then on the prime vertical. It appears evident this is seen in profile, as it inclines downward at an angle of 10 or 12 from the perpendicular. It does not seem very distant. 12 P.M., the aurora still bright, but the brightest part is now west of the pole, before it was east.

"13th. 6 A.M., clear, east and north; bank of cirrus in N. W., _i.

e._, from N. N. E. to W. by S.; irregular branches of cirrus clouds, reaching almost to south-eastern horizon; wind changed (S. E. fresh); 8 A.M., the sky a perfect picture; heavy regular shafts of dense cirrus radiating all around, and diverging from a thick nucleus in north-west, the s.p.a.ces between being of clear, blue sky. The shafts are rotating from north to south, the nucleus advancing eastward.

"At noon (same day), getting thicker (S. E. very fresh); 6 P.M., moon on meridian, a prismatic gloom in south, and very thick stratus of all shades; 9 P.M., very gloomy; wind stronger (S. E.); 10 P.M., very black in south, and overcast generally.

"14th. Last night, above 12 P.M., commenced raining; 3 A.M., rained steadily; 7 A.M., same weather; 8.20 A.M., a line of low storm-cloud, or scud, showing very sharp and white on the dark back-ground all along the southern sky. This line continues until noon, about 10 at the highest, showing the northern boundary of the storm to the southward; 8 P.M., same bank visible, although in rapid motion eastward; same time clear overhead, with cirrus fringe pointing north from the bank; much lightning in south (W. fresh); so ends.

"15th. Last night a black squall from N. W. pa.s.sed south without rain; at 3 A.M., clear above but, very black in south (calm below all the time); 9 A.M., the bank in south again throwing off rays of cirri in a well-defined arch, whose vortex is south; these pa.s.s east, but continue to form and preserve their linear direction to the north; no lightning in south to-night.

"16th. Clear all day, without a stain, and calm.

"17th. Fine and clear (N. E. light); 6 P.M., calm.

"18th. Fair and cloudy (N. E. light); 6 P.M., calm.

"19th. Fine and clear (N. fresh); I. V. visible in S. W.

"20th. 8 A.M., bank in N. W., with beautiful cirrus radiations; 10 A.M., getting thick, with dense plates of cream-colored cirrus visible through the breaks; gloomy looking all day (N. E. light)."

The letters in a parenthesis signify the direction of the wind.

During this month there were three distinctly marked periods of belts of showers, preceded by "fresh" or "strong" south wind, and followed by the N. W. There was a period when a belt of less intense stratus, without much wind, occurred (28th, 29th, and 30th of June). This was followed by a distinct belt of showers and _fresh_ S. wind, on the 2d of July, and by the N. W. wind and clear weather, on the 3d.

During the rest of July it was more irregular, with the exception of the 7th, 8th, and 9th, when another belt and revolution occurred.

Now, these periods, when distinctly marked, exhibit the same succession of phenomena--viz., elevation of temperature, fresh southerly wind, belt of condensation, c.u.mulus or stratus with cirrus running east, but extending south, followed by N. W. wind, and clear, cold air. Can any one believe they were successive rotary gales?

I wish, in this connection, to make a suggestion to Lieutenant Maury and others. The descriptions of M. Ba.s.snett, although not perfect, are very intelligible. He describes things as they were, and as they should be described. He distinguishes the clouds, and the scud, and other appearances.

But Colonel Reid's descriptions are unmeaning and unintelligible. G.

M.--Gloomy, misty! Gloomy from what? fog, or stratus, or a stratum of scud, or what? We can not know. Again, C. The table tells us this stands for detached clouds. But of what kind? c.u.mulus, broken stratus, patches of cirro-c.u.mulus or cirro-stratus, or scud? All these, and indeed every kind of cloud or fog formation, except low fog, may exist in detached portions.

These abbreviations will not answer; they do not describe the weather. The clouds must be studied and described. There is no difficulty in doing it.

Sailors will learn them very soon after their teachers have; and those who teach them should see to it that the logs contain terms of description which convey the meaning which may, and ought to be, conveyed. The use of these indefinite terms can not be continued without culpability.

Again, the observations of seamen off our coast are in accordance with the progress of this cla.s.s of storms on land, and prove that they continue S.

E. over the Atlantic, abating in action as they approach the tropics.

There is abundant evidence of this in the work of Colonel Reid, and the charts of Lieutenant Maury, but I can not devote further s.p.a.ce to them.

The third cla.s.s form in the counter-trade, over some portion of the country, from excessive volume or action of the counter-trade, or local magnetic activity, without coming from the tropics or being connected with a regular polar wave of magnetic disturbance.

The following diagram exhibits their form, progress, and accompanying induced winds.

[Ill.u.s.tration: Fig. 22.]

The gentle rains of spring, particularly April, and the moderate and frequent snow-storms of winter, are often of this character; and so are the heavy rains, which commence at the morning barometric minimum, rain heavily through the forenoon, and light up near mid-day in the south, followed by gentle, warm, S. W. winds. This cla.s.s are more frequent in some years than others--probably the early years of the decade, while polar storms are, during the later ones. It is this cla.s.s which have _violent_ easterly winds _in front_, and on the _south side_, with two or more currents, and which Mr. Redfield has also supposed to be cyclones.

The fourth cla.s.s are isolated showers, occurring over particular localities, or belts of drought and showers alternating; sometimes a general disposition to cloudy and showery weather for a longer or shorter interval over the whole country; at others, limited to particular localities in the course of the trade. Such a period occurred during the wheat harvest of 1855. This cla.s.s I attribute to a general increased magnetic action, but it may be induced by an increased volume, or greater south polar magnetic intensity of the counter-trade, exciting and concentrating the regular currents of the field, and increasing their activity and energy. These also often work off south gradually, and are followed by a cold N. W. air for a day or two; showing a tendency, in the excited magnetism, to pa.s.s as a wave toward the tropics.

The following diagram will give some idea of this cla.s.s:

[Ill.u.s.tration: Fig. 23.]

There are sometimes very obvious local tendencies to precipitation over portions adjoining an area affected with drought, as there are other magnetic irregularities over particular areas.