amount of its specific heat. While the land changes its temperature very considerably with the diurnal and annual alternations, the sea does so to a less degree. During the night, the effect of water upon the coast is to warm, and in the day to cool the land. The same results are produced on the change of the seasons: both the spring and autumn are later. Places on the shore of large bodies of water have frequently a clouded sky, and these arrest the rays of heat from above, as well as prevent its loss by radiation from beneath. Therefore, island or coast climates are never subject to such extremes of weather as are those of the interior. M. Boussingault states that the temperature of London and Paris is about the same, while the latitude of the latter is nearly three degrees lower.

As we travel from the coast toward the interior, the difference between the mean temperature of summer and winter is much greater than on the seaboard. Rivers, lakes, and ponds possess to some extent the same power of equalizing temperature, according to their size; and therefore we can perceive the great value of isothermal lines established by Baron Von Humboldt, which are a guide to the general temperature, independent of the parallels of latitude.

By reference to an isothermal map which gives the mean temperature of the United States for the four seasons, we shall ascertain that this mean

NATURE OF STORMS.

29

degree is the same at Fort Snelling, Minnesota, and at Boston; while there is a difference in the latitude of these places of two and a half degrees. The autumn of the former is colder than that of Boston; therefore, if we possessed no more information, we should determine that the growing season was shorter and colder than that of the Atlantic coast, and that fruits which succeed near the latter would not flourish in Minnesota. But we must remember that the effect of ocean upon the coast in the spring is to cool it; and, consequently, that the ground at Fort Snelling becomes sensible of the warm spring sun much quicker, and is free from the cooling influence of the water all summer. The mcan spring temperature is like that of Southern Connecticut or New York. Those fruits which hardly reach maturity in the Northern Atlantic States, ripen fully and much earlier there, because the heat of spring and summer is so much more intense.

From the manner in which altitude, exposure, and the presence of bodies of water affect climate, the importance of considering atmospheric influences in the selection of sites for our orchards must have become evident. Let us investigate further the general phenomena which produce good or bad results in the growth of fruits.

1. The nature of storms. The difference in these

and in the climate east and west of the Rocky Mountains is very marked. The prevailing winds of our continent are western. Although the eastern district comprises a most extensive area in several latitudes, yet its general features are similar. It is subject to great extremes, a cold winter, and a semi-tropical summer. The variety of its indigenous plants is very great. The vapor arising from the Gulf of Mexico is condensed as it passes over the land, and, falling until it is taken by this western current, it is spread over the whole eastern portion of the continent. When these winds are most severe, as in the autumn, when the trees are laden with fruit, as well as in early spring, the importance of shelter in exposed positions will readily occur to every practical cultivator. But this will be considered hereafter.

While there are some benefits resulting from the variableness of temperature in the Eastern States, there are also serious disadvantages, such as the destruction of the fruit-buds of the most tender species and varieties in the more northern States, and the encouragement of the fungi, as well as of other diseases incident to a sudden check or acceleration of the sap-flow.

On the contrary, the climate of the Pacific coast is characterized by great equanimity. If the discases resulting from sudden changes and extremes of temperature exist at all, it is in their most ameli

orated form. The temperate climate of Spain finds there a rival; and the wine-grapes of Germany, Italy, and even those of our hothouses, succeed there perfectly. The thermometer seldom falls below fortyseven degrees Fahrenheit, or rises above sixty.

2. Snow storms. The benefits and evils resulting from these are about equal. Upon strawberries the effect is decidedly good, as it defends the tender crown-buds which are to produce the fruit of the next year. The result is the same upon all small fruits, such as currants, gooseberries, and raspberries, as it modifies the extremes of temperature. When the snow has melted, if the water stands upon the gound, the subsequent effect may be disastrous it becomes frozen, and settles down upon strawberries, frequently occasioning their death. The cause may not be uniform; sometimes it may be owing to the exclusion of air: and yet it is difficult to understand that plants in a dormant or frozen state should require air. If the snow first melts, then freezes, it forms a crust of ice, that may act as a lens to concentrate the sun's rays and burn the plant. The presence of ice upon the ground about all trees or plants is very dangerous. The radiation of heat from the tree near the surface of the ice prevents it from being frozen so solid that the plant. cannot move, else the result might not be so ruinA little unfrozen belt surrounds the tree, and

ous.

against the sharp edge of the ice the tree is blown by the wind until the bark is cut through, when the plant is completely girdled. The sap passes from the roots to the leaves, through the wood of the tree, and this will not be impeded by the wound; but as the juice descends in the liber, or inner bark, it finds its course stopped, and the superfluous sap produces a large swelling in its endeavor to provide a channel. If the cut is not very wide, and the injury has taken place recently, so that the lower edge of the bark is still fresh, a junction will sometimes be formed. If, however, the case be otherwise, it will be necessary to resort to artificial means.

The strongest and most luxuriant shoots of the previous year's growth may be cut a little longer than the width of the wound, and after the ends are sharpened upon both sides, they may be placed under the bark above and below, - the flat side of the shoot facing the centre of the tree, thus bridging over the cut.

Heavy falls of snow, such as we frequently have in the northern parts of the country, sometimes do great injury. As it melts in the spring, it breaks down the spreading limbs, and makes most unsightly wounds. In such localities, those varieties which naturally produce such limbs should be avoided; or, if cultivated, the branches should not be allowed to start from the trunk lower than the average height of snow during the winter.