The Irish potatoe, (solanum tuberojum) presents another remarkable instance of the effects produced upon plants by a change of climate, This plant is of little value within the tropical climate of America, where it was first discovered by Europeans; but when transferred to, and cultivated in colder climes, it becomes one of the most prolific food bearing plants known to man. It is a fact generally known to the people of the United States, that the potatoe gradually improves in quality as we proceed from the gulf of Mexico to the northern Lakes. This improvement in the quality of the potatoe, we suppose to be produced by the economy of the plant in protecting the tuber from the greater degree of cold in the more northern latitudes. It is a common practice with the planters of the south to procure seed potatoes from the more northern districts; and no one doubts, that, the first crop from these seed is much better than potatoes grown from those raised in the south. The potatoes raised the first year from northern seed are considered but little inferior to those produced further north; after this they rapidly decline, and in two or three crops become adapted to the climate and are no better than other southern potatoes. This plant propogates from both the flower seed and the tubus; this provision in its economy evinces the extreme care which nature has taken to ensure the perpetuation of its species against accidents which might possibly happen to the seed produced from the flower. The inherent, and natural mode of propogation is by the flower-seed, and the tuber is a mere adjunct, to be used as an expedient in case the flower seed should fail; and is to be considered simply as a part of the old stock.Hence, in time, the offspring from the tubus is liable to decay, upon the same principle that a particular variety of fruit decays by being propogated for a long time by grafting.

From this view of the economy of the plant, we are naturally led to submit a few suggestions upon the subjet of disease known as the "Potatoe-rot." When we subject a plant to cultivation, it is important to study its economy, and understand its native or normal habits; to the end that we may give them the proper direction without do

ing too great violence to its nature. Therefore, to insure the largest, and most permanent advantage from the culture of the potatoe, we must conform to the original economy of the plant, by propogating from both the seed and the tubor. The produce of the first year from the flower seed, is too small for the purposes of food, but it should be frequently raised for the purposes of planting; otherwise, violence will be done to the economy of the plant, which will induce a tendency to decay; and although the race may survive for many years, yet from its enfeebled condition it is rendered liable to injury from causes which would not affect it, if it were in a more healthy state.

It becomes less capable of resisting unusual changes of temperature, and unusual seasons of draught or moisture, it is more choice in its location, and requires a soil and culture congenial with its diseased condition; and, finally, it is more liable to the attack of insects, and the fungie, many of which are doubtless bred upon the plant by reason of its state of incipient decay. Many causes have been assigned for the potatoe-rot, and some of them are probably true, but we think these must all be regarded as proximate causes merely; and that the first cause is the violation done to the economy and habits of the plant in continuing to produce it from the tuber beyond the time limited by the laws of its nature; and until this cause is removed the plant will be liable to fail from many causes and accidents which would never happen, or, if happen ing, would not affect it were it in a healthy and vigor ous condition.

Aware that many learned men have been ingaged in the investigation of this subject, we have offered these views with diffidence; but believing that they are predicated upon true principles of natural economy, we submit them for what they are worth. A few years of experiment and observation would be sufficient to test the principle, and if it should be found true, it will more firmly establish the value of the Potatoe, as well as the capacity of the potatoe producing districts to sustain their population; and besides restoring the inhabitants of those districts to a state of plenty, it will impart con

fidence in the future prosperity of the country. The people of the United States as well as of Europe are deeply interested in this subject; for, notwithstanding the potatoe has not suffered so much here as in Ireland, yet, if the cause of this disease be what we have supposed, it must soon become destructive to the crop here as well as in other countries; and the sooner the true cause can be ascertained the less will be the danger of suffering from it.

The potatoe is another of the great staples of America, and takes its true position on the northern confines of the corn growing region; and will enable our most northern districts to support a population much greater in numbers, than could have been sustained by the growth of any other plant in that region. By the culture of the potatoe our most northern districts are capable of supporting as dense a population as almost any other part of the Union; provided, the health of the plant can be permanently relied upon. Owing, however, to its bulky and perishable nature, it can never enter largely into commerce so as to make it a sourse of great wealth to the country.

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It is a very remarkable fact in the history of the tatoe, that the plant should have been produced by nature in a climate so different from that which is best adapted to its usefulness, and, that, from being little better than a worthless weed, it should become the means of supporting so large a portion of the human family, not only on the continent of its discovery, but in Europe and Asia also.

The history of many other valuable plants would be found both curious and interesting, but these must suffice for our present purpose. We have selected those which are most important, as well as most familiar to the American people, that the reader might have an opportunity of comparing our observations with his own, as well as of testing the soundness and accuracy of our de. ductions.

The mean annual temperature of a given district of country cannot be relied on as a correct indication of its suitableness to the production of a particular plant; to en

able us to judge whether a certain plant will succeed in a given climate, we must first understand its habits and economy, and by ascertaining both the mean and extreme temperature, as well as the duration of winter and summer, and also, of spring and autumn, we can then form an opinion in regard to its adaptation.In the United States, the difference betwen the mean temperature of winter and summer is much greater than in Europe; hence many annual plants which require but a short time to grow and ripen, are produced in great perfection in this country, which would not mature in those even where the mean annual tempearature is perhaps much higher. On the other hand, many perennial plants will stand the mild winters of Europe, which cannot survive the frost of our climate of equal mean temperature.

The meteorology of a country exerts an important influence upon plants; and should be studied and understood by all who are engaged in either agricultural or or horticultural pursuits. The quantity and frequency of both rain and dew are influenced by causes readily ascertained by observation, and are generally determined by the peculiarity of location. In a country which is diversified by mountains, or high hills and deep vallies, a very short distance frequently makes a great difference in the quantity of rain that falls, especially in summer, when rain is most required.

Dew is formed more abundantly in vallies and near water courses, than in more elevated and exposed situations; and is favorable or otherwise to the growth of plants according to their nature.

Winds, also, exert much influence upon the growth of vegetation by accelerating evaporation, and depriving succulent plants in dry situations of the moisture necessary for their more perfect developement; elevated table lands, or, other localities exposed to constant or unusual currents of wind, are therefore unfavorable to the growth of plants which require much moisture. And furthermore, unless these winds should come from the direction of the Equator, they lower the temperature in the spring season, and greatly retard the growth of tender plants.

We have frequently observed the growth of the young cotton plant to be materially affected in the northern part of the cotton growing region, by exposure to western winds.

All these meteorological phenomena, as well as change of climate, tend more or less to modify the habits and economy of plants; and they are therefore highly worthy of the observation of every individual who is in any way interested in their cultivation, either for use or ornament.

A thorough knowledge of these subjects would save much labor as well as expenditure that is often lost by experiments, which, owing to physical causes can never succeed; and would enable the agriculturist to select from the whole vegetable kingdom the plants which were best adapted to his particular locality.

From some one or more of these causes it often happens that a certain plant which succeeds well in one locality cannot be profitably produced upon a neighboring farm; and hence we frequently hear it said that an individual is not lucky in producing some particular plant. This want of luck, is, doubtless in many cases, owing to the want of skill and industry; but it is nevertheless true, that many individuals labor, through perhaps their whole lives, against some of these causes, without ever having discovered the reason of their failure. And such must continue to be the case, uutil the agriculturist shall become better informed in regard to these subjects; and in the mean time, the word "unlucky" should be understood as implying ignorance, rather than mischance, or accident. To the individual who should desire to purchase a farm for the purpose of producing any certain plant, a knowledge of the local causes which influence its growth, would be of great importance in directing him in the choice of a suitable location.

All the cultivated fruits are very choice in their location; and some of these are so peculiar in this respect, that no artificial means have been found sufficient to make them productive and well flavored in locations uncongenial to their nature. Some of the European fruits have hitherto resisted all our efforts to naturalize them, so far