EFFECTS OF LOCALITY ON TEMPERATURE. 



BY VARDLEY TAYLOR, LOUDON CO., VA. 



In the last number of the third volume of 

 the Horticulturist, is a short communication 

 from James Grant, Davenport, Iowa, giving 

 some account of the cold weather in the pre- 

 vious winter. Mr. Grant considers it as 

 disproving the opinion of a former writer, 

 that peach blossoms are always killed when 

 the thermometer is 14° below zero. He says 

 " the trees protected by our bluffs will have 

 as much fruit as they can hold. For days, 

 during the winter, the thermometer was 20° 

 below zero. The preservation of our trees 

 was probably owing to deep snows and uni- 

 form cold weather." There are so many 

 modifying influences, in respect to cold wea- 

 ther, caused by difference of elevation and 

 exposure, either east or west, the presence of 

 large borders of water, protection by bluffs, 

 or other elevations, &c., that it is difficult to 

 calculate the effect of cold on blossom buds, 

 until ascertained by actual results. Were a 

 series of observations made on such occur- 

 rences, in different sections of our widely ex- 

 tended country, giving minutely the situatiop, 

 difference of elevation of places, and of all 

 other circumstances bearing upon the sub- 

 ject, with the effects in each case, much in- 

 formation might be elicited ; and that branch 

 of meteorology would not only be better un- 

 derstood, but the probable effect of different 

 localities for particidar fruit trees be ascer- 

 tained with more certainty. 



With this view, I propose furnishing for the 

 pages of the Horticulturist, our experience of 

 the cold of last winter, with a theory of its 

 effects, corroborated by our previous experi- 

 ence. This district of country is peculiarly 

 liable to great changes of temperature, situated 

 as we are in the first valley between the two 



first ranges of mountains above tide-water, 

 with the Blue Ridge — that great feature in 

 the Apalachian system of mountains of the 

 Atlantic slope — on the west, and one of its 

 spurs — the Catoctin mountains — on the east. 

 This valley has an elevation of from 4 to 600 

 feet above tide-water, while the mountains 

 rise from 2 to 600 feet above the valley. 

 Such difference of elevation is frequently 

 marked by great difference of temperature, 

 even at the same time. The peaches are 

 often killed by the frosts of spring or the cold 

 of winter, in the lower grounds, while on 

 high situations or on the mountains, they arc 

 rarely injured by either. Indeed, in some 

 places a crop may be calculated on with per- 

 haps as much certainty as in any part of our 

 country, where frosts are liable to injure 

 them at all. When the N. W. winds pre- 

 vail, they bring the air of the Alleghany 

 mountains to us, modified, it is true, by mix- 

 ing with the air of the valley over which it 

 passes, but still often in winter exceeding 

 cold. A prevalence of south or southeast- 

 erly wind in a little time will bring the warm 

 air of the Atlantic or of the Gulf of Mexico, 

 and produce an opposite extreme. Hence, 

 the variations of temperature here are often 

 great. But the thermometer never falls ae 

 low in high windy weather, unpleasant as it 

 is, as it does in calm weather, after a snow 

 has fallen. Last winter the snow fell to the 

 depth of several inches, and the clouds pass- 

 ed off without wind, and it continued calm 

 for several days, when one morning the ther- 

 mometer indicated 14 ° below zero, and it is 

 probable, from the effect produced, had it been 

 ascertained in our lowest valleys, it would 

 have been much lower. My orchard has a 



