As good tiles as I ever saw were dried in a different way, and not rolled at all. As they were taken from the machine--six at a time--each carrier passed off with his tray, and placed them _on end_ carefully, upon an _even floor_. When five or six rows of tiles were thus placed, the whole length of the drying-house, a board was set on edge to keep them from falling to one side; then followed five or six other rows of tiles, and so on, till the drying-ground was filled. This was the plan adopted in a tilery near Dublin, some years ago. It is only a few days since I examined some of the tiles made at these works, which had been taken from a drain, where they had been in use for nine years; and the _clear ringing sound_ produced by striking them against each other, showed what little effect that length of time produced upon them, and how well they had been manufactured. _Cost of Tiles._ We have recently paid at the works-- For 1-1/2 inch pipes 17s. 6d. per thousand. " 2 " 25s. " " 3 " 45s. " Each tile one foot in length, and the one and one-half-inch pipes weighing 16 cwt. per thousand. One of the great difficulties in connection with tile-making is, in many districts, to procure clay sufficiently free from lime. Tiles are very often sold by sample, sent a considerable distance, and it becomes necessary to test them, which we do (for lime) by placing them in water for a night; and, if lime is present in the tile, it will, of course, swell out, and break the latter, or leave it in a riddled state. I have now endeavored to answer the queries in your postscript, and I have carefully avoided enlarging on some points in them with which your readers are already familiar. If I shall have thrown a single ray of additional light on this subject across the Atlantic, I shall be amply repaid for any attention I have given to thorough-drainage during the past twelve years. I should here observe that I mislaid amongst my papers the portion of your letter containing the queries (it was a separate sheet), and it has not as yet turned up, so that I had to depend on a rather treacherous memory to keep the queries in my mind's eye. It is highly probable, therefore, that I have overlooked some of them. This circumstance was the chief cause of the delay in writing. You are quite at liberty to make any use you please of this communication. WILLIAM BOYLE. INDEX. Absorption of moisture; 303, 304, 322 " Fertilizing substances; 268 Aeration; 269, 276 Albert Model Farm; 375 American experiments; 367 Anderson, J. F.; 112 Arrangement of drains; 173 Artesian Wells; 83 Attraction, adhesive; 301 " capillary; 302 " of soils for vapor; 304