1870. 



NEW ENGLAND FAIRER. 



117 



KOZEN dew is of- 

 ten called hoar 

 frost. As the 

 ' air grows cool- 

 er at eveniDg, 

 the vapor con- 

 tained in it is 

 condensed into 

 minute drops; 

 and deposited 

 upon the sur- 

 face of the 

 earth, leaves, 

 «S;c. The air 

 continuing to 

 grow cooler, 

 until it reaches 

 the freezing 

 the minute 

 drops are changed into ice. 

 In the act of freezing, 

 water expands, so that ice occupies more space 

 than it did in the form of water. This is a 

 fact of great importance. To it are due most 

 of the effects of frost, as they present them- 

 selves to us, and as they relate to agriculture. 

 It is this expansion that causes ice to float on 

 the surface of water. This floating ice pro- 

 tects the water covered by it, from the action 

 of the air, and thus retains the water in a 

 liquid state. Were it not for this benevolent 

 provision, the whole body of the water in the 

 ponds and lakes would become solid, and all 

 Animal and vegetable life in the water would 

 be destroyed. As it is, a great amount of la- 

 tent heat is retained in the water, and the life 

 of tishes, insects and water-plants is preserved. 

 That the ice preserves the heat in the water is 

 proved by the fact that the atmosphere may be 

 10° or 20° below zero above the ice, while 

 below it, the water is 32° or more above zero. 

 When water penetrates the soil it does not 

 form a chemical union with it, but merely a 

 mechanical mixture. Such particles contained 

 in the soil as are soluble are dissolved by the 

 water. This merely causes a finer division of 

 such particles. The insoluble particles retain 

 a large amount of water, entangled as it were, 

 among them, and held by a sort of capillary 

 attraction. When the surface of the ground 

 freezes, or rather when the water in the super- 

 ficial stratum of the ground freezes, the parti- 



cles of water expand and separate the particles 

 of earth from each other. Then when the ice 

 melts and the water evaporates or settles into 

 the ground, the earth is left porous and mel- 

 low, so that it can admit the air and be pene- 

 trated by the roots of plants, and the radicles 

 of germinating seeds. 



Most soils above the line to which the frost 

 penetrates, never become comparatively hard 

 and compact, owing to the expansion of the 

 water contained in them, in the act of freez- 

 ing. "When soils in grass or grain contain a 

 great deal of water near the surface, the freez- 

 ing of the water raises or throws up the sur- 

 face, and as this surface is bound together by 

 a net-work of roots, it is raised irregularly, 

 and broken into lumps and fragments, as we 

 often see in the spring, indicating the use of 

 the roller to reduce it again to a level condi- 

 tion. 



In peat meadows the stratum through which 

 the frost penetrates is always loose and 

 spongy and must be entirely removed before 

 the peat is cut for fuel. In this case there is 

 so much water frozen that the particles of soil 

 are removed so far apart that they do not at- 

 tract each other, and unite again into a solid 

 mass. 



When soils are ploughed late in the fall, the 

 water more readily penetrates them, and hav- 

 ing been broken and loosened by the plough, 

 their particles are more readily separated, and 

 the spi'ing finds them in a more mellowed con- 

 dition, and ready for earlier handling. 



The fluids contained in the vessels of plants 

 consist chiefly of water. In the vessels of 

 grasses, weeds and green crops generally, a 

 comparatively slight degree of cold freezes 

 these iluids and ruptures the containing vessels 

 and stops the circulation. Hence such plants 

 die and soon become dried up, as we see in 

 the autumn. 



The sap in trees is mostly contained in the 

 vessels of the liber, or inner bark, and the al- 

 burnum or sap-wood. These vessels are some- 

 what better protected and will endure a lower 

 degree of temperature. 



In the unripened wood of vines and late 

 growing trees, as peach trees, for example, 

 which contain a large amount of sap, the ves- 

 sels are ruptured by a moderate degree of 

 cold, their bark shrivels and the wood dies. 

 This is Nature^s method of shortening in such 



