NEW ENGLAND FARMER. 



239 



THE TERM OF PERPETUAL CONGELA- 

 TION. 



As we ascend in the atmosphere, the temperature 

 of the air diminishes with our altitude, by a rate 

 somewhat affected by seasons, hours of the day, &c., 

 but which is generally one degree of Fahrenheit's 

 thennometer for every 343 feet of elevation. This 

 is the average rate, for it is not uniform. Near the 

 earth, the diminution of temperature, as we ascend, 

 is very rajjid ; then again, more gradual ; and again, 

 at very lofty elevations, accelerated. By ascending, 

 therefore, at any latitude, we reach a point where 

 moistiirc is always congealed. This point is of course 

 highest at the equator, and lowest at or near the 

 poles ; and for other latitudes, at intermediate points 

 of elevation. An imaginary line, extending from the 

 equator to the pole, forms the curve of perpetual 

 congelation. In the accompanying diagram, AB 

 represents the height of the term of perpetual con- 

 gelation at the equator, — about three miles, — and 

 the line BC represents the line of latitudes, while 

 AC represents the curve alluded to. 



70° 



.50° 



iO'^ 

 30° 



20" 

 10° 



S 



CO 



w 



It meets the surface of the earth before reaching 

 the pole, as it is well known perpetual frost sur- 

 rounds the poles. In our latitude, the altitude of 

 the term of perpetual congelation is about nine 

 thousand feet. The cirrus cloud, as we have before 

 stated, consists of the frozen vapor above this limit, 

 while the other varieties of clouds float below it. 



The cause of the intense cold of the upper regions 

 of the atmosphere is not at first view obvious, since 

 the general law respecting heat (or hot air) insures 

 its elevation. The upper portion of air in a room is 

 warmer than the lower strata : and the atmosphere 

 is heated by conduction, coming in contact with the 

 heated earth. It is so transparent that the sun's 

 rays are not absorbed by it, in their passage through 

 it. Another general law, however, is here interposed 

 to prevent the escape of this genial atmosphere, so 

 essential to the e-\istcnce of animated beings. That 

 law is — llarefaction causes a diminution of tena- 

 pcrature — an increased capacity for caloric. Intense 

 cold is produced in the vacuum of an air-pump ! 

 Sir John Ilcrschel has recently proposed a practical 

 application of this principle, — in which, however, he 

 was anticipated by one of our own countrymen, — 

 maintaining a uniform, low temijcrature, in an iso- 

 lated space, as a room, freezing water, &c. The at- 



mosphere decreases ver%' rapidly in density, as the 

 altitude increases ; the heated air, rising, expands ; 

 this rarefaction causes dimmution of temperature, 

 and hence an equilibrium is soon reached. Local 

 circumstances fre(iucntly modify the application of 

 tins principle. The frost or snow line is not always 

 at the same elevation, in the same latitude, on differ- 

 ent sides of the equator. In Cliili, latitude 41^' south, 

 the lower limit of perpetual snow is six thousand 

 feet. The air is sometimes very mild in elevated 

 districts. Valleys are warmer than level plains of 

 the same altitude, as the hills reflect and radiate 

 heat to them. In Switzerland, spots of verdure may 

 be found in the midst of perpetual snow and ice. 

 The Glacier of Grindenwald, in the canton of Berne, 

 covering twelve hundred square miles, has upon its 

 borders not only trees of hardy growth, but delicate 

 verdure. It is also said, that upon the Ilimalayah 

 mountains, extensive pastures exist in valleys which 

 are fifteen thousand feet above the level of the sea. 

 — Fa in ihj Visitor. 



TO PRESERVE FLOWERS. 



Procure a flat dish of porcelain, into which pour 

 water. Place upon it a vase of flowers, and over the 

 vase a boll glass, with its rim in the water. The air 

 that surrounds the flowers, being confined beneath 

 the bell glass, is constantly moist Mith water that 

 rises into it in the form of vapor. As fast as the 

 water becomes condensed, it runs down the side of 

 the bell glass into the dish, and if means be taken to 

 enclose the water on the outside of the bell glass, so 

 as to prevent it evaporating into the air of the sitting- 

 room, the atmosphere around the flowers is continu- 

 ally damp. The plan is designated the " Hopean 

 Apparatus." The experiment may be tried on a 

 small scale, by inverting a tumbler over a rose bud, 

 in a saucer of water. — Selected. 



PARSNIPS. 



A correspondent has written to inquire " whether 

 we know, by ouj- own experience, the quality of the 

 parsnip for feeding and fattening pigs." In answer, 

 Ave beg to state that at our farm at Catlands Bing- 

 men, we have been in the habit of employing pars- 

 nips for that purpose, for some time. Upon reference 

 to our books, we find that on the eleventh of Octo- 

 ber, 1S47, we put up two shoats of eleven weeks old, 

 and fed them on skim milk and parsnips, for three 

 months, when they Avcre killed, weighing two hun- 

 dred and thirty-one pounds. They were Avell fat- 

 tened, firm in flesh, and the meat of excellent flavor. 

 The quantity of parsnips consumed by them was 

 nine bushels each. — Sussex {Eiiylish) Express. 



We have often wondered that no account is made 

 of this valuable root. All the world is alive to the 

 value of the carrot, while this esculent is entirely 

 overlooked. That the parsnip contains more saccha- 

 rine matter than the carrot, or even any of the beets, 

 we are satisfied. A very excellent wine is made of 

 it, which we venture to assert cannot be made from 

 any other of the whole root crop. Its estimation, as 

 an edible for the table, also tells in its favor. And a 

 herd of hogs, turned i)\to a field containing bagas, 

 beets, carrots, and parsnips, would not be long in 

 settling the question which they like the best ; and 

 as they cannot read the Genesee Farmer, and arc not 

 influenced by any of our blundering theories, and 

 trust alone to experience, and that uncrrmg guide, 

 instinct, in the place of reason, we are disposed 

 to give them the credit of being very capable judges 

 — very. — Genesee Farmer. 



