Governor Wright, of Indiana, in a public address, estimated the marshy lands of that State at 3,000,000 acres. "These lands," he says, "were generally avoided by early settlers, as being comparatively worthless; but, when drained, they become eminently fertile." He further says: "I know a farm of 160 acres, which was sold five years ago for $500, that by an expenditure of less than $200, in draining and ditching, has been so improved, that the owner has refused for it an offer of $3,000." At the meeting of the United States Agricultural Society, at Washington, in January, 1857, Mr. G. W. P. Custis spoke in connection with the great importance of this subject, of the vast quantity of soil--the richest conceivable--now lying waste, to the extent of 100,000 acres, along the banks of the Lower Potomac, and which he denominates by the old Virginia title of _pocoson_. The fertility of this reclaimable swamp he reports to be astonishing; and he has corroborated the opinion by experiments which confounded every beholder. "These lands on our time-honored river," he says, "if brought into use, would supply provisions at half the present cost, and would in other respects prove of the greatest advantage." The drainage of highways and walks, was noted as a topic kindred to our subject, although belonging more properly perhaps, to the drainage of towns and to landscape-gardening, than to farm drainage. This, too, was found to be beyond the scope of our proposed treatise, and has been left to some abler hand. So, too, the whole subject of reclaiming lands from the sea, and from rivers, by embankment, and the drainage of lakes and ponds, which at a future day must attract great attention in this country, has proved quite too extensive to be treated here. The day will soon come, when on our Atlantic coast, the ocean waves will be stayed, and all along our great rivers, the Spring floods, and the Summer freshets, will be held within artificial barriers, and the enclosed lands be kept dry by engines propelled by steam, or some more efficient or economical agent. The half million acres of fen-land in Lincolnshire, producing the heaviest wheat crops in England; and Harlaem Lake, in Holland, with its 40,000 acres of fertile land, far below the tides, and once covered with many feet of water, are examples of what science and well-directed labor may accomplish. But this department of drainage demands the skill of scientific engineers, and the employment of combined capital and effort, beyond the means of American farmers; and had we ability to treat it properly, would afford matter rather of pleasing speculation, than of practical utility to agricultural readers.