j 5 THE FARMER AT HOME. 



by way of experiment. The most simple method, however, of pro- 

 ducing cold by the evaporation of water, may be applied to various 

 useful purposes," especially in warm countries ; thus sailors are accus- 

 tomed to cool their casks of liquors, by sprinkling them with sea- 

 water 



Dr. Darwin justly observes, that the evaporation of moisture from 

 the surface of the earth, produces so much cold as to injure those ter- 

 restrial plants, which are too long covered with it. Hence, such 

 parts of wall trees as are sheltered from the descending dews, by a 

 coping stone on the wall, are not so liable to be injured by frosty 

 nights ; because they are not made colder by the evaporation of the 

 dew, and also have less water to be congealed in their vessels, and to 

 burst them by its consequent expansion. 



EVERGREENS. Are a species of perennials, that preserve 

 their old leaves a long time after the formation of the new, and do 

 not drop them at any determinate time. In general, the leaves of 

 evergreens are harder, and less succulent, than those which are 

 renewed annually. The trees are generally natives of warm climates ; 

 and the common evergreens are those belonging to the pine and 

 spruce families, of which the white pine, hemlock, black spruce, yew 

 trees, fir balsam, and arbor vitse, may serve as specimens. In orna- 

 mental planting, evergreens are very desirable ; and where they can 

 be successfully transplanted constitute one of the greatest beauties 

 of the landscape. Their rich foliage amid the frosts and snows of 

 winter is inimitably rich and magnificent. Some herbaceous peren- 

 nials, as the house-leeks, and naval-worts, enjoy the same privilege 

 with the evergreen trees, and resist the severities of winter ; some can 

 even exist out of the earth for some time ; being replete with juices, 

 which the leaves imbibe from the humidity of the atmosphere, and, 

 which, in such plants, are of themselves sufficient for effecting the 

 purposes of vegetation. For this reason, unless in excessive hot 

 weather, gardeners seldom water fat succulent plants, as the aloes, 

 which rot when they are moistened, if the sun does not quickly dry 

 them. The leaves of all the evergreen shrubs and trees have a thin 

 compact skin over their surface, as is easily discovered by macerating 

 them in water, to separate the parenchyma, or pulp, from the vessels 

 of the leaves ; which cannot be effected in any of these evergreens till 

 a thin parchment-like cover is taken off. They are found by experi- 

 ment to perspire but little, when compared with those which shed 

 their leaves ; and it is, perhaps, principally owing to this close cover- 

 ing, that they retain their verdure, and continue through the winter 

 on the trees. The nutritive juices of these plants always abound, 

 more or less, with an oily quality, which secures them from being in- 

 jured by severe frost, so that many evergreens grow in the coldest 

 parts of the habitable world. 



EXCRETIONS. From experiments that have been made by 



