the fine material necessary in making substitutes for Dinas bricks, which method is fully described in this chapter.

The clay mill shown in Figs. 93 to 97 is a good contriv ance for both the mixing and reduction of fire and other clays, and will work them into either a fine, semi-fine, or coarse condition.

Figure 93 is a top or plan view of the machine. Fig. 94 is a side elevation. Fig. 95 is a sectional view on the line x x of Fig. 94. Fig. 96 is a top view of one of the crushing-rollers, with a portion broken away to show the cutters located therein. Fig. 97 is a side view of Fig. 96, showing the operating mechanism.

Referring to the drawings, A designates the reducingrollers or cylinders, mounted in suitable frames or supports, B B. The reducing-rollers A A are mounted so as to revolve in opposite directions, as indicated by the arrows. The invention consists in subjecting clay, clay shale, etc., to the disintegrating and reducing action of rollers having a varia

ble peripheral outline, so that the clay to be operated upon will be subjected to rapid peripheral action of one coming in contact with the less rapid peripheral action of the axis of the adjacent roller. It also consists in providing the crushing-cylinders with peripheral slotted perforations, through which the clay is forced by the pressure and abrading action.

of the rollers into the interior of the cylinders and subjected to the action of cutters or beaters; also of knives or beaters located within the disintegrating-rollers, whereby the clay which is forced through the peripheral openings of the rollers is still further reduced.

It is well known that it is practically impossible to reduce or disintegrate clays or the harder clay shales, by impingement alone. Pressure exerted in two directions, as in the case of two impinging rollers rotated at the same speed, only flattens or flakes the clays without disintegrating them. Even the hardest rock or quartz resists, to a greater or less degree, disintegration by such means, while by the action of this and the following machine the clay or other material is subjected to a rubbing action between the impinging surfaces, while a part thereof is forced into the slotted openings, to be acted upon by the rapid-rotating knives or beaters, and is effectually reduced to the required condition.

The periphery of a roller travels faster or has a greater velocity than the axis. Consequently, when the clay is caught between the rollers, it is subjected to the action of the periphery of the roller acting against the centre of the adjacent one. The effect will be a rubbing or abrading action, which will thoroughly disintegrate the clay, and not crush or compress it only, which is the action of ordinary reducing-rollers. The rollers A are provided with a series of slots or perforations, a, in their peripheries, which extend through the same and open into the interior of the cylinders, and through which the clay is forced to be operated upon by revolving knives or beaters located within the rollers.

CC are the cutters, arranged spirally on and around a common centre or hub, which is mounted in bearings in the ends of the cylinders A, and are provided with pinionwheels bb, which mesh with a larger pinion-wheel, C1, secured to the central shaft or axis of the rollers or cylinders A, so that by the revolution of the cylinders A the knives C will be rotated with greater velocity, and the clay which has been forced into the rollers through the slots a will be cut or sliced into minute particles, and owing to the spiral position of the knives, the prepared clay is thrown to one end of the cylinders and out through the openings d, arranged for that purpose.

The cylinders A A are provided with pinion-wheels D D, which mesh with each other and with a pinion-wheel E, on the main driving-shaft F, said driving-shaft being mounted in suitable bearings, and provided with a pulley-wheel G, or other means for imparting power to the machine.

His the hopper through which the material to be disintegrated is fed to the rollers, which may be made adjustable by any of the well-known means, so as to reduce the material to any desired degree of fineness.

Figs. 98 to 100 show a modification of the clay mill above described, and it is by the same inventor.

Fig. 98 is a side elevation. Fig. 99 is a top view. Fig. 100 is a detached view of the crushing or reducing-rollers.

Referring to the drawings A A designate the reducingrollers, mounted in a suitable framework B. The reducingrollers A A are made elliptical in peripheral outline when

mounted to rotate in opposite directions, as indicated by the arrows in Fig. 100, such elliptical form compensating for the convergence incident to the changing or alternating po

sitions of the rollers when rotated in this direction, and are hung in proper bearings at a point eccentric to their axes, and so timed that when they rotate at the same velocity the faces or peripheries of each of the rollers will constantly touch or impinge against each other during their respective rotations, so that a rapidly-changing peripheral speed is given