A very good yoke of oxen will cost when well broke, and about five years old, if well matched and of good size' from 80 to 100 dollars. They continue good, without accident, and with good usage, until ten years old; then they are usually fatted, and bring from the butcher according to their size and fatness from 100 to 120 dollars. Whether oxen are not more susceptible of _heat_ than horses, I am ignorant. My opinion is that they are. A circumstance in your climate to be ascertained in forming an opinion of their comparative utility. With respect to "deep ploughing," a considerable change is producing in this state, in the opinion and practice of farmers in this respect. Deep ploughing begins to be more general than formerly. I should state _five_ inches to be the most approved practice, on turning up the sord for corn. With respect to deepening it for other crops, after the sord is broken, it depends upon the nature of the crop and the resources of the farmer, and also the state of his soil. My own rule is never to lay down land to grass until it has been turned up to the depth of _fourteen inches_. But my practice is peculiar, as I carry a regular succession of, 1st corn, 2d potatoes, 3d carrots, 4th grain, 5th grass, over my whole farm; considering, as I do, that _carrots_ is of all farm products the most profitable, and using them as the test of the actual state of the depth of tilth on my farm. Undoubtedly when the depth of ploughing pass the old tilth, and enters upon the virgin soil, "manuring" must be in proportion to the depth of the virgin soil, which you turn, otherwise you sacrifice present crop to future crops;--a practice very discouraging to any farmer. I enclose you the newspaper account of our last cattle show. A more detailed statement will appear in our Repository. Respectfully, I am your humble servant, JOSIAH QUINCY. GEO. W. JEFFRIES, ESQ. SUGAR MAPLE. A letter writer in the Albany Statesman, in giving an account of the New York canal, says--