To redeem the promise with which my last article closed, I shall proceed at once to consider the causes of the failures of some varieties of pear that ordinarily do well on the quince, and that, in other positions on my own farm, are among the thriftiest of my trees. These causes constitute some of the most prominent objections to the substitution of the quince for the pear stock, in the cultivation of the pear.

The quince is a native of Japan. "The climate," Malte-Brun says, "is variable, abounding in genial rains;" that "during the autumnal months, particularly," the season of all others most trying to our fruit-trees, "much rain falls;" and adds, "it is a country in which thunder is heard almost every night in summer, and where showers and hurricanes abound." In the recognition of the fact that nature has adapted the quince to those of its native islands, may we not divine the reason of the admission by horticulturists, that the quince delights in moist places, and are warranted in saying it still retains, and, in obedience to nature's law, ever will retain, a demand for those conditions of soil its constitutional adaptations require.

With this stand-point, we can respect the authority of our fruit culturists, when they tell us "it will thrive where the cultivation is rich and deep,^ for the reason that if the substratum of soil is highly retentive of water, there the requisite degree of moisture for thrifty growth may be secured. Without this, failures will occur that will disappoint the expectation of the culturists, and give discrepancy of testimony to their teachings, while each may be in perfect harmony with their experience.

In one part of my orchard, the dwarfs have proved a decided failure - the part, too, where, the reader will bear in mind, the trees had enjoyed the richest culture, and received the greatest care - while those removed to a distant part of the same field, exhibit great precocity of growth. The cause is to be found unquestionably in the fact that the soil of the latter is underlaid by a clay substratum, while that of the former is a gravelly loam.

Downing says: "The quince grows naturally in rather moist soil, by the side of rivulets and streams of water." Thomas adds: "The soil for the quince should be deep and rich - a rather moist soil has been preferred by many, though not essential - deep and enriching cultivation being of incalculably more importance." The importance of deep and rich cultivation we admit, but unless.it be in connection with a moist soit - such as a proper substratum only will give you in our climate - failures will be the rule, and successful culture the exception, as fruit culturi8ts will testify when their observations are made matter of record. And since, in all probability, but few of those who have embarked in the growing of the Pear on the quince have been aware of the necessity of studying the habitudes of the stock, it will be strange, indeed, if expectations of success should fail to be realized from this cause alone.

But the most weighty objection to the general introduction of the dwarfing of the Pear is, that in a great majority of cases the orchard-trees, especially, will not receive sufficient attention to secure success. A Pear-tree, once established in any soil of moderate tilth, will take care of itself, will ordinarily find nutriment enough to secure vigorous growth, will at least make progress in the world, and bear fruit. Not so with the dwarf. The range its rootlets travel for food is circumscribed. Numerous as those rootlets are, they will soon exhaust the soil of the food nature has supplied, and if attention is not given it - and good attention, too - it very soon shows its neglect. And good feeding is not all that is required. If well fed, it will give you towering shoots; these you must repress. But, with this, your work is not done. Your spring pruning, laboriously completed, is soon followed by a call for June pinching. And, again, your autumn shortening must not be neglected, or your reward for high culture will consist in great luxuriance of growth, which, though pleasing to the eye, will not satisfy the palate. ' And, furthermore, in orchard culture, in our country of abounding high winds, with occasional thunder-storms, the culturist who neglects to shorten-in will sometimes find the reward for his labor unexpectedly given in a prostration of his heavy-laden trees, and his hopes together.

The separation is so readily made at the usual swelling over- - just at the junction of the graft with the stock - that it is not unusual, under these circumstances, for this accident to occur.

This repressing of the wood force by the usual spring pruning, June pinching, and August shortening-in of the shoots, when described to the novice, appears more like play than work; and, when demanded by the few pet dwarfs in the garden of the amateur, is truly pleasant recreation, but, to the orchardist - with knife in hand - the work of thus preserving a due relation between the wood and fruit principles in his hundreds of trees that have already attained the size good cultivation for a number of years has given them, is the imposition of no slight task. Very few have any adequate idea of the labor demanded, and fewer, still, when they learn it have moral courage manfully to meet it. Untrained laborers cannot here be trusted - one's own hands, or those of a judicious gardener, must do the work.

Cowper has well expressed the feelings of the orchardist on this subject, when he says: - "These, therefore, are his own peculiar charge; No meaner hand may discipline the shoots, None hat his steel approach them".

"He disposes neat At measured distances, that air and sun, Admitted freely, may afford their aid, And ventilate and warm the swelling buds".

Touching the varieties worthy of general cultivation on the quince, I would fain speak reservedly. As yet, my experience is too limited to warrant saying much. Happy would I be, Mr. Editor, if some one of your able correspondents would come to my relief, and take up the thread of the subject just at this point.

Mr. Rivers, that most accomplished English pomologist, says, out of one thousand varieties of Pear in cultivation, he grows but four for the Covent Garden market - three of these are on Pear stock, the Louise Bonne de Jersey alone on quince. No judge of Pears will dare to lift his voice disparagingly to the character of that most rapid growing variety, uniformly bearing abundant crops of well-formed fruit, which, though not of the highest flavor, is yet such a pleasant subacid, as to be a universal favorite.

Our experience in this country certainly demands that the Duchess d'Angou-leme should, of all others, be cultivated on the quioce - the more vigorous growth of the tree - together with the improvement in the quality of the fruit, secures to it, in my judgment, above all others, a substitution of the quince for the Pear stock.

I have not, Mr. Editor, said all of what I had designed to say on this subject; and, if you will accept as an apology my present pressing engagements, even to weariness, in the garden, and orchard, for discontinuing, for a time, the completion of the series, when another season has enlarged my observations, I promise a return to it, unless, in the mean time, some abler hand shall render the labor superfluous.