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scholar, the late David Watson, (of Louisa county,) in a similar period of five years, from 1823 to 1828. His residence was near the South West mountains, and in a country comparatively thickly covered with wood. The result of his observations and those of Mr. Jefferson, making a distance in time of 52 years, and of southern latitude in favor of Williamsburg, is here submitted:

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The coolest and warmest parts of the day were separately added, and an average of the greatest cold and heat of that day was formed. From the averages of every day in the month, a general average for the whole month was deduced. In following this mode of analysis, there are many slight features of discrepancy between the statements of Mr. Jefferson and Mr. Watson, which considerably impair the correctness of the comparison. Mr. Watson's thermometer was suspended in a passage, far removed from the action of fire, in a house constructed of wood; and the calculation of his table is based on observations made between the hours of 10 A. M. and 3 P. M. Mr. Jefferson is silent as to the situation of his thermometer, while it appears that he has reckoned from the hours of 8 A. M. to 4 P. M. The hottest period of these five years, observed by Mr. Watson, was in July, 1825, when the thermometer on several days rose above 90°, and the hottest month was in August, 1828. The coldest period was during the month of January, 1827, and the warmest winter was in 1828-29.

My own observations made during a period of four years, from 1829 to 1834, cannot be calculated for an average temperature. Many days and even months from my absence from home, were necessarily unnoticed. Those periods which are recorded differ but little in their particular and daily results, from those of Mr. Watson; while I have noticed his singular omission-the prevalence of the winds, and the "fantastic tricks" with which our climate so playfully disports. From my observations, I am induced to place the mean temperature of our climate at 55°; thus varying according to natural and artificial causes several degrees from the standard temperature of the sea.

The year 1831 was characterised by many vicissitudes of heat and cold. On the 27th February the mercury sunk to 70, while in July and August it frequently rose to 86° and 94°. The ensuing winters of 1831 and 1832 were uncommonly rigorous, snow fell in great quantities, and in many places continued on the ground till the 4th of March. Early frost did much injury to vegetation, while the cold was but slightly removed from the earth

until late in the ensuing summer. The spring of 1834 was attended by severe frosts, which resembled in their destructive character, those which had rendered the year 1816 proverbial. They committed great devastations in April, and on the 15th, 16th, and 17th of May, the Indian corn on our low lands, and the leaves of the garden and forest trees were scathed and blighted to a degree precluding, in many cases, all hope of restoration.

In Virginia the transitions from heat to cold are sudden, and sometimes to very extreme degrees; often in the day time the mercury will stand at 94° or 81°, and will fall in the course of a few hours to 60° and 50°. Mr. Jefferson informs us that the mercury has been known to descend from 92° to 47° in thirteen hours. I have frequently noted vicissitudes of a similar kind, and when the change is accompanied by a S. E. wind and rain, the air becomes cold, raw and disagreeable. We have few summers in which a fire is not often required. On the 1st of May, 1827, there was a light fall of snow at Gloucester Court House,* while it is not uncommon to see slight frosts in August. In our winter the cold weather, though severe, is short, and the frequent snows of the night are generally removed before the sunset of the ensuing day. Water in ponds is slowly congealed, and rarely makes ice thick enough for preservation, until it has been chilled by a fall of snow-again, its production is very rapid; rivers half of a mile in breadth, will be frozen over in the course of one night, sufficiently firm to bear men and horses. In the month of January, 1827, many of those short yet wide salt streams, which wash the shores of Gloucester county, were frozen to the extent of thirty or forty feet from the land. This rigo rous cold is rarely of much duration. Sustained, and principally created by north and northeastern winds, it quickly yields to the shifting of the wind to any other point. Some of our winters are so temperate and mild, that the cattle can find a support in the woods. Vegetation has been observed in all the winter months, and in the latter part of December diminutive pears, peaches and apples, fully ripened, have been gathered from the trees. A rose, exposed in an open garden, bloomed throughout the whole winter of '28 and '29. In this winter the peach tree bloomed in the latter part of January, and produced in its regular season a plentiful crop of fruit. Many of our coldest days are succeeded by gentle and moderate evenings; our severest cold is about the latter part of January, generally commencing after a hard rain, and continuing on an average about six days, thus realising the truth of that old Virginian proverb, "that as the day lengthens the cold strengthens; a rapid thaw, often accompanied with rain and east winds, then takes place, while warm days and moderate nights soon reduce its severity, and open the way for the premature approach of spring. "Halfe of March" is no longer winter. Spring has already scattered her vivid mantle o'er the scene, while the whole air is redolent of life and fragrance. Yet even its brightness is momentary-an unexpected frost often shows that the frown of winter still lingers on the land, and we too frequently find a practical illustration of Shakspeare's metaphor,

"The tyrannous breathings of the north,

Checks all our buds from blowing."

*Dr. Rush in his essay on the climate of Pennsylvania, mentions a fall of snow at Philadelphia on the night between the 4th and 5th May, 1774.

+ Mr. Jefferson tells us that in 1776 York river was frozen over at York town, and in 1780, Chesapeake bay was solid from its head to the mouth of the Potomac. The cold winters of 1784 and 1814 still live in the recollections of tradition,

It is now stormy, variable and cold; now calm, gentle and warm, and now dry, peaceful, and serene. Until the middle of May our climate presents one incessant tumult of rain and drought, frost and heat; yet a spring uni formly cold is far more favorable to our agriculture, than its usual uncertain temperature for suppressing vegetation, it protects it from the blighting frosts of March and April. Often during the spring months the weather is excessively damp, cloudy and hazy. In March, 1833, the sun was obscured for more than thirteen days, while every thing was chilled into gloomy melancholy.

The vegetation of this season affords us a criterion of the heat of the spring, which may be received in aid of the more accurate results derived from the thermometer. In the course of four years I have found these ave rage periods of time suststained by careful observations:

Peach blooms from March 7 to March 14.
Apple blooms from March 20 to March 29.
Cherry blooms from March 13 to March 17.
Plum blooms from March 26 to March 31.

Strawberry blooms from March 24 to March 31.*

About the latter part of May our summer has commenced: the air be comes dry, warm and elastic, and the verdure of the forest assumes a more deepened hue of vivid green. The superabundant moisture of the earth acquired during the winter, is now thoroughly evaporated, and the temperature of the season in dispelling lassitude, invigorates into activity. Summer burns on with a bright and glowing splendor, alternately relieved by gentle showers and refreshing breezes. Occasional droughts of many weeks in duration, parch the luxuriance of the vegetation-they are succeeded by copious and heavy showers of rain, which quickly restore the withered prospect. The approach of autumn is marked by heavy fogs in the morning and evening, which are soon dispelled, leaving that calm and serene temperature, which gives to this season all the beauty of tranquil repose. In every season there is a large and constant exhalation from the earth in the shape of vapor, its volume being proportioned to the heat of the day. We do not often observe this exhalation when the heat of the atmosphere differs in a small degree from that of the earth; when the temperature of the air is considerably lower, this vapor so soon as it has arisen is deprived of a part of its heat, while its watery particles are more closely attracted into union and become visible in the shape of fog. In the autumn of Virginia, the heat of the day is sufficient to produce a large ascent of vapor. Undisturbed by currents of wind it easily condenses, and is thickened by calm and chilling nights into a heavy mist, which in the guise of a cloud finds its resting place on the earth. Autumn of all other seasons, is least liable to sudden and extreme vicissitudes. The approach of winter is alike gradual and uniform, and though we have frequent light snows, the mildness of autumn is rarely wasted away until late in December.

In reasoning from the researches of philosophy, we are taught to place but little reliance on the uncertain narratives of tradition; they, however, with a slow yet steady advance, acquire respect, and often mould theory into fact, and fashion opinion into fixed principles. The common belief that our

* At the residence of R. G. Esq. near the Natural Bridge in the valley of Virginia, these fruit trees in the year 1834, bloomed at the following periods:

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April 1.
April 15.

climate has been changed into a milder temperature, has taken most of its certainty from the statements of our old people, who are uniformly consistent in this particular. The bloom of the orchard trees formerly restrained by a protracted winter from premature expansion, rarely failed arriving at the maturity of fruit; the earth remained covered with snow for many weeks, and the winter did not, as now, dally with the wantonness of spring. The marshes, uncleared lands, ponds and lakes, which conspired to absorb the heat of the earth,* have been almost obliterated or greatly reduced. There is a lesser quantity of snow, and more of rain, while the frequency of violent storms of wind in the spring and summer, distinctly prove the great mass of our local heat, and accumulated electricity.

The winds of Virginia are singularly fickle and capricious, possessing neither the uniformity or regularity of those which blow at the tropics. Our prevailing wind is the south west, which assumes, alternately, gentle and severe characteristics. The frequency of southwestern winds above the latitudes of the trades, flows as a necessary consequence, from the continuance and direction of the vast currents of air. It moves unconfined and unresisted over the sea, until it reaches that unbroken range of mountains, which towers from one extremity of our continent to the other. It strikes against them, and from its elasticity rebounds with great velocity, in a direction opposed to the forcing powers of the trades, taking in its oblique movement all those features which mark our southwestern wind.

During the spring the N. E. is the most common wind. The huge masses of snow and ice at the north pole, are gradually melted by the heat of the sun; great quantities of vapor during this time are exhaled and remain suspended, augmenting both the weight and bulk of the atmosphere. That wonderful and mysterious agent, electricity, in dispelling the vapor and converting it into elastic air,f gives an impetus to that wind which issuing from the poles, takes a northeastern direction as it advances southerly, (its diurnal motion being less than that of the earth,) and falls surcharged with snow and rain on every portion of our country.

Mr. Jefferson made 3698 observations on the various points from which our winds blew, noting their changes two or three times in each day. The prevalence of the S. W. winds, over those from other quarters is thus numerically stated by him:

South West,

North,

North East,

East,

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He has also made a comparative view of the difference between the winds at Monticello and Williamsburg. He has reduced nine months' observations at Monticello, to four principal points, being perpendicular to, or parallel with, our coasts, mountains, and rivers, viz: the N. E., S. E., S. W., and N. W. He has also reduced an equal number of observations, 421, from his table above, taking them proportionally from every point.

* This principle is apparent from the fact that marshy countries are always cold; the decrease of temperature after a violent rain, also proves its truth. An unusual evaporation carries off the heat of the earth, and may we not reasonably expect a cold winter after a wet summer?

+Through a glass tube filled with water, Dr. Franklin passed an electric shock, the tube was shattered to pieces, and the water disappeared; a similar experiment was tried with a tube filled with ink on a sheet of white paper, the same effects were produced, the paper being neither stained nor discolored.

My own observations made many times in each day, amount to 749, without reducing them in the proportionate manner of Mr. Jefferson. I have submitted them under the points and heads which he has adopted:

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In an average of two years, I have found our winds thus yearly prevailing; the dominant wind of each day being only reckoned, and not the usual vicissitudes of local breezes, or squalls.

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A curious phenomenon is sometimes witnessed during a severe wind from the S. W.; a thin vapor or scud is seen moving with great velocity below the clouds, from the N. E., there being two currents of air of directly contrary courses in active motion at the same time.

In the early part of the spring and autumn, in dry seasons, about sunset it is common to meet with currents of warm air, small in their extent yet extremely rapid in their movements; they are considerably above the heat of the human body, and are wayward and eccentric, both in their duration and extent. Their existence has given rise to much speculation, and even the experienced philosophy of Mr. Jefferson has succumbed to the mystery of their origin.

Our frosts are sometimes equally severe and unexpected. No body placed near the earth has a temperature of its own, but is entirely regulated by that of the earth. A violent storm of rain, by absorbing much of the heat When the power of of the earth, is often followed by a destructive frost. frost reaches a certain pitch, the vapors dispersed throughout the air, yield their latent heat-the atmosphere becomes clouded, the frost is either destroyed or mitigated, and the vapors descend in rain or snow.

Our hardest frosts never penetrate the earth more than three inches, and though the leaves of the trees and shrubs are scathed or destroyed, and timber sometimes splits in the direction of the fibres of the tree, its roots uniformly remain uninjured. Those portions of vegetation which grow nearest to the earth, and those in low and marshy situations, receive the severest injuries. On the night of the 17th May, 1834, the leaves of the oak, hicko

May they not proceed from that latent electricity, which pervades the air most in dry seasons, and which is attracted to the human body by its heat,-thus producing from the action of affinity, the feeling of sudden warmth?

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