13 ON SUDDEN ALTERNATIONS OF TEMPERATURE. [Appendix^ 



following instructive letter from an ably conducted monthly jo'irnal published 

 at Albany, in the State of JNew-York, under the title of the CiiUivator. It is 

 extracted from the Number for March last : — 



" In regard to Irish potatoes, a still thinner covering of earth than the one 

 just mentioned suffices with us to preserve them from rotting. Indeed, it would 

 seem as if they could freeze and thaw several times, during winter, without 

 being destroyed, provided they are covered with earth all the time ; for we often 

 find them near the surface and peifectly souiad, in the spring, when spading up 

 the ground in which the crop had grown during the previous season. There 

 they must have undergone freezing and thawing whenever the earth was in 

 either state, as it often is to a much greater depth than the potatoe roots ever 

 extend. Why should those roots always be destroyed when they freeze above 

 ground, and not suffer equally when frozen under ground ? 



" The reason why potatoes, apples, &c. become soft, and rot when frozen 

 and then thawed suddenly, uncovered and in open air, is the sudden thawing. 

 You may put a heap of apples on the floor of a room, or other dry place, where 

 they will freeze perfectly hard, and if covered close with any thing that will ex- 

 clude the air, when the weather becomes warm enough to thaw, the apples will 

 remain sound and uninjured, after they are thus closely thawed. The cover 

 may be of the coarse tow of flax, or any inicle that will cover them close and 

 exclude the air. So apples may be packet, in a tight barrel, if full and headed 

 up so as to exclude the air. They may be suffered to remain so in a gaxret, or 

 any dry place where it freezes hard, and they will be found sound and free from 

 injury, if the barrel remains tight till they are thoroughly thawed. It is the sud- 

 den thawing that causes the apples or other vegetables to become soft and rot, 



" So if the fingers on your hand be frozen, and you expose them to sudden 

 heat by warming them at the fire and they suddenly thaw, the flesh will morti- 

 fy and slough off. But, if you freeze your fingers or other limbs, and put them 

 in snow, and rub gently till they thaw, — or if put into a pail of water just drawn 

 from the well, which will be less cold than your frozen fingei-s, — they will thaw 

 slowly, and suffer but little injury. 



" So during the early autunmal frosts in September, if the morning after the 

 frost is cloudy, the frost will be slowly drawn from the frozen vegetables, and 

 they will be uninjured ; but if they receive the rays of the early and clear sun, 

 they thaw so suddenly, that they will hang their heads and perish. If wet with 

 water from the well, long enough to extract the frost before the sun shines on 

 them, they do not suffer. 



" Onions are a difficult root to keep in winter. If they are put in a cellar 

 warm enough to save them from frost, they will vegetate awd be deteriorated. I 

 put them in the warehouse, where they freeze as hard as if out of doors. If in 

 a heap, I cover them close with some old clothes, or any thing that covers close, 

 to exclude the air. The same if in boxes or casks. They freeze hard, but it 

 does not appear to injure them for present use, if thawed by putting them into 

 a pail of fresh-drawn water, to draw out the frost just before cooking them. 

 Onions, thus kept, will be in good condition in the spring, after thawing under 

 cover from the air. 



" I put parsneps, carrots, beets, &c., in boxes or casks, and then cover them 

 with potatoes, wnich preserves them from drying." 



In farther illustration of this subject I need only recall to the recollection of 

 the gardener the well known fact, that, when the winter frosts begin to set in, 

 and his finest flowers to be nipped, those continue to blow the longest, on which 

 the sun's rays fall latest in the day. Dahlias protected in this way, will bloom 

 occasionally for weeks, after those which regard the eastern sky are completely 

 withered. 



Professor Lindley has published a series of valuable observations on the effects 

 of extreme cold upon plants. The general results of these observations are 

 ■tated in his ^^ Theory of Horticulture," p. 88. But the conclusions at which 



