218 



FARMERS' REGISTER— CLIMATE OF VIRGINIA. 



closely attracted into union and become visible in 

 the shape of fog. In the autumn of Virginia, the 

 heat oi" the day is sufficient to produce a large as- 

 cent 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 i'esting place on the 

 earth. Autumn of ail 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, its mildness 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; the}^, however, 

 with a slow yet steady advance, acquire respect, 

 and (often) mould theory into fact, and fjishion 

 opinion into fixed principles. The common belief 

 that our climate has been changed into a milder 

 temperature, has taken most of its certainty fi-om 

 the statements of our old people, who are uni- 

 formly consistent in this particular. The bloom of 

 the orchard trees formerly restrained by a pro- 

 tracted 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 wanton- 

 ness of spring. The marshes, uncleared lands, 

 ponds and lakes, which conspired to absorb the 

 heat of the earth,* have been almost obluerated or 

 gi'eatly 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 as- 

 ^sumes, alternately, gentle and severe characteris- 

 tics. The frequency of south v/estern winds 

 above the latitudes of the trades, flows as a ne- 

 cessary consequence, from the continuance and 

 direction of the vast current 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 elas- 

 ticity rebounds with great velocity, in a direction 

 opposed to the forcing powers of the trades, tak- 

 ing in its oblique movement all those features 

 which mark our south western wind. 



During the spring the north east 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, aug- 

 menting both the weight and bulk of the atmos- 

 phere. That wonderlul and mysterious agent, 

 electriciiy, in dispelling the vapor and converting 

 it into elastic air,t gives an impetus to that wind 



* 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 ofl' the heat of the earth, and may 

 we not reasonably expect a cold winter after a wet 

 summer ? 



t Through a glass tube filled with water. Dr. Frank- 

 lin passed an electric shock, the tube was shattered to 

 pieces, and the water disappeared; a similar experi- 



which issuing from the poles, takes a north eastern 

 direction as it advances southerly, (its diurnal mo- 

 tion being less than that of the earth,) and falls 

 surcharged with snow and rain on every portion 

 of our country. 



INlr. Jeflcrson 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 south west vvinds, over those 

 Irom other quarters is thus numerically stated by 

 him: 



South west, 926. North, 409. 



North, 611. West, 351. 



North east, 548. South east, 223. 



East, 521. South, 109. 



He has also made a comparative view of the dif- 

 ference between the winds at Monticello and Wil- 

 liamsburg. He has reduced nine months' ol)serva- 

 tions at Monticello, to four princijjal points, being 

 perpendicular to, or parallel with, our coasts, moun- 

 tains, and rivers, viz: the north east, south east, 

 south west, and north west. He has also reduced 

 an equal number of observations, 421, from his 

 table above, taking them proportionally fi-om every 

 point. 



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: 



N. E. s. E. s. w. N. w. Total. 



Williamsburg, 127 | 61 | 132 | 101 | 421 

 Monticello, 32 | 91 | 126 | 172 | 421 



Braynefiekl, . 204 | 130 | .247 | 168—749 



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. 



365 days. 



A curious phenomenon is sometimes witnessed 

 during a severe wind from the south west; a thin 

 vapor or scud is seen moving with great velocity 

 below the clouds, from the north east, 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 du- 



me.nt was tried with a tube filled with ink on a sheet 

 of white paper, the same efl'ects were produced, the 

 paper being neither stained nor discolored. 



