rough, cracked, and shelly, when burnt, and often fall to pieces. Beside, it must be observed, that the same degree of moisture is not suitable for the fabrication of pipe tile of different diameters. Large pipes are made of stiffer clay than small ones. If clay of the proper temper for making inch pipe were pressed through a four inch mold, not a single piece would be found perfect-every one would be flattened and distorted. Experience is the only guide, and by this alone can a proper acquaintance with the matter be obtained.

Whatever method may be adopted for removing small stones from the clay, it is very necessary that this clay should be pugged, except, indeed, in such very rare cases as the clay formation at Cleveland.

1. The Pug Mill of tile yards differs little from that commonly used in the manufacture of bricks; the only material difference being in the arms or pins by

which the clay is tempered. The clay being used

in a much stiffer state for tiles than bricks, iron knives are needed for cutting the clay, in the place of wooden pins. These knives are made strong and sharp, and when set in the upright shaft, the advancing edge is raised a little, so that the effect of their movement is to press the clay downward toward the opening. Instead of several iron knives, some use a smaller number of heavier ones, and these have riveted into them, at right angles, a number of short knives, which are so arranged as to pass each other somewhat closely, and serve to cut the lumps of clay to pieces thoroughly.

The subjoined cut represents the section of an excellent pugging mill. It consists of a cylindrical body, well bounded by stout hoops-the upper portion expands outward from the body, so as to form a hopper or funnel, into which clay is thrown. A stout iron bar, a, a, is placed in the center of the body, so as to revolve. This center bar is furnished with stout iron armatures, b, placed on alternate sides of the bar; the armatures furnished with three teeth, c, one of which is placed on the upper side of the armature, and just midway between the two which are placed on the lower side. Wherever this mill has been used, it has given the most ample satisfaction.

2. The Roller Mill, which is found necessary in some localities, consists of two iron rollers, each about fifteen inches in diameter. Some prefer to have one roller

smaller than the other, so that if they revolve in equal times, the surface of one will move faster than that of the other, and combine a rubbing with the crushing movement. This, however, is probably of no real benefit, and is attended with the disadvantage of not feeding as well as a mill where the rollers are both large. The rollers are about thirty inches in length; they are thick, but not solid, and should weigh about 400 pounds each. They are cast in an iron mold or chill. This secures a perfectly hard and smooth surface, and much more durability than when they are cast in the common sand molds. The shafts of the rollers work in boxes lined with babbit metal, which, by means of set screws, are made to slide upon the iron frame, and give the rollers any degree of closeness that may be desired. From one-eighth to one-sixth of an inch is a distance that will permit no stones to pass, large enough to do mischief, either in moulding or burning. The gearing of the mill should be so adjusted to the power, as to give only about ten to fifteen revolutions of the rollers in a minute. A rapid movement not only requires a greater force, but greatly increases the danger of breakage of the machinery. A plank hopper is set over the rollers, large enough to hold a wheelbarrow full of clay. To the underside of the iron frame, on which the rollers rest, it is necessary to attach scrapers of iron or steel plate, to scrape the clay from the rollers, otherwise they will clog and become immovable. In setting the mill, it should, if possible, be elevated four or five feet above the level of the yard, and placed on horizontal timbers of some length, rather than upon posts set immediately under. The object of this is to secure space for the ground clay under the mill. The whole expense of such a clay mill, at the Cuyahoga Steam Furnace, in Cleveland, will be about one hundred dollars.

3. The Horse Power to drive the mill, whether the endless chain or lever power be used, should be arranged for two horses. A single horse, unless very strong, or the mill be geared for a slow movement, will, if there be many stones, or the clay be very lumpy, find the work rather severe. It is better, therefore, in the first instance, to obtain a power on which two horses may be used, if necessary, or a single horse, if one is found to be sufficient. If the clay be dug up in the fall or winter, and thoroughly frozen, or if it be turned over and well wetted a few days before grinding, the work will be much easier; if taken fresh from the bank or hillside, and ground immediately, a good deal of additional power will be required.

Tile Machines.—It would be a useless task to describe all the different forms of tile presses in use. All possible forms of construction have been used, but those known as Clayton's or Whitehead's, are among the preferable kinds. These ma

chines are strong, simple, and require comparatively little power to drive them and are not apt to get out of repair.

A passing description of both these machines may be introduced with propriety. The clay box of the Clayton press consists of a perpendicular cylinder, terminating below in the mould box. The cover of the clay box is a kind of piston head, which is made to drive the clay downward, while working, by means of a cogged piston rod, in the cogs of which mash the cogs of a small wheel, which is driven by a larger cog-wheel, and this in turn by a smaller cog-wheel attached to the handle or working lever of the machine. The pipes are pressed out at the bottom, and hanging free, are received upon the prongs of a fork, which correspond in number to the number of pipes pressed out at one time. The tiles are cut off by a wire, which is attached to the machine. Two cylinders properly belong to this kind of machine, one of which is removed when emptied, and replaced by the other full. Latterly, this machine has been so modified, that the pipes are forced out horizontally, and received upon a truckle bed, and are not cut off until this is full, when they are separated and borne away upon forks.

Whitehead's machine has a flat lying quadrangular box, closed by a cover. In front is the mold, and by means of a cogged piston rod, the plunger, consisting of the entire posterior end of the box, is driven forward, which presses the clay through the mold. When empty, the action is reversed, the plunger again becomes the back wall of the box, the cover is raised, more clay is filled in, and the work proceeds again. The cogged piston or plunger rod is worked horizontally, by means of three cog-wheels meeting with each other, as do those of the Clayton machine. The pipes are received upon a truckle-bed as they are expelled.

Neither of these machines is without its advantages and defects, and yet six or eight thousand tiles can be molded daily, by some of the latter machines, while the former may be made to produce more, and is therefore better calculated, perhaps, for use in large manufactories. Proper machines can be manufactured after models, in almost any machine shop, but purchasers should always take care to secure good and warranted machines.

Mons. Barrall, in his excellent treatise on drainage, gives a detailed description, accompanied by engravings for the most part, of fifty-nine different tile machines, used in England, France and Germany. Many of these machines are very expensive, but at the same time, manufacture a large number of tiles daily. One machine which is there figured and described, would require eight active boys to carry away the tiles as fast as they are made- each boy taking six tiles at a time. In this country several gentlemen have invented machines for the manufacture of tiles. Of those in most general use in this State, are the Mattice & Penfield

machine and the Daine's machine. We present a cut and a short description of each,

This machine not only grinds the clay, and molds the tile, but places them upon the drying boards. 4, represents the die; 3, the tile; and 2, 2, the drying boards, which are cut the length of three tiles; and placed upon the carriage, 1, the portion of which, under the machine, is covered with an endles belt, upon which these boards are placed, on the rear of the carriage, and are drawn under by the tiles as they issue from the die, and deposit themselves upon the boards. 7, 7, is a frame held together by the handles, across which small wires are stretched, 8, 8, for the purpose of cutting the tiles. This frame is movable, for the purpose of cutting the tiles where the end of the board occurs.

6 is the shaft which passes through

the machine, upon which iron knives FIG. 33.-MATTICE & PENFIELD'S DRAIN TILE

are fastened to grind the clay. To the lower ends, eccentrics are fastened, that move the plunger in the clay box, to which the die, 4, is fastened. 5, is the lever by which the cut-off plate is driven over the clay box, after it is filled, to prevent the clay from pushing back up in the machine when the plunger pushes it out. 9, is the yoke upon which a slide is fastened, driven by an eccentric on the shaft that moves the lever, the plunger throwing it back when making the plunge, where it remains, leaving the cavity open again. A, is the sweep. The machine makes a plunge at every turn of the shaft. Less than one-fourth of the time required to make a turn of the shaft, makes a plunge, which gives the man that cuts them ample time to do so, and set them in drying racks, which are placed upon hand barrows for the purpose of moving them when dried to the kiln.

The American Tile Maker.-The Tile Maker is only eight feet in length, including aprons. It is mounted upon wheels, and is simple in construction, easily kept in order, and not liable to accident from any ordinary cause. It will make horseshoe or sole tile of any size, according to the nature of the die which may be used; the power applied to drive the clay through the dies is the screw worked by a

sists of a lid, which lifts with a handle, and which, when the clay is filled in, is shut and fastened by strong iron latches on each side, which swing into their place by weights. The other two feet of the frame is occupied by the iron tube, in which the screw of the piston or plunger works, which is worked by a handle attached to a small balance wheel; attached to the end where the tiles are made,

small balance wheel, as shown in the engraving. This machine is made of cast iron, and consists of a box set on feet, to which are attached small wheels, by which it can be moved from place to place. The iron box or frame is about five feet in length, and fourteen inches wide; at one end is fastened the die, which is easily taken off or put on by screws. The box into which the clay is put, and in which the square plunger compresses the clay through the die, to form the tile, is the main division of the frame, and occupies about two feet in length; one-half of this division is covered with an iron plate, screwed down solid; the other con