There are several makes of stoners, but most of them work on this principle, whether the rod is lifted by hand or moved by a crank. [Illustration: FIG. 111. Parts of Universal grinder.] [Illustration: FIG. 112. Vegetable slicer.] =202. Grinders.= Grinders are of two principal types--the roller and the burr. Coffee and other hand mills are of the burr type (Figs. 109 and 110). The food passing between these rough surfaces is ground to a fine powder as one is turned on the other. =203. Choppers or Meat Grinders.= Choppers or meat grinders, as they are sometimes called, consist of a spiral channel, thru which the food is pushed along. Knives are placed in the sides of some machines to chop the food as it passes, while in others the knives are only at the outlet. Keep the fingers out of the hopper when the chopper is being operated. Keep the machine clean and dry when not in use (Fig. 111). [Illustration: FIG. 113. Universal vegetable slicer.] =204. Choppers.= Choppers have been made which really chop the food without crushing it, but these machines are so clumsy and noisy, that they have not come into common household use. They consist of chopping knives which are raised and lowered by levers and a crank. =205. Slicers.= Slicers vary in design. The following illustrations (Figs. 112 and 113) show two different types. Care must be taken to guard the fingers when using slicers. Wash the knives and keep them dry when not in use. A soiled knife gets dull faster than a clean, dry one. =206. Lard and Fruit Presses; Sausage Stuffers.= Presses and stuffers are of two types--the one which depends on the weight exerted on a long lever, and the other which depends on a screw to press the substances. The screw forces a flat board or surface down upon the food as it is turned. More pressure for the size of the device can be secured with the screw than is practical with a weight on the long arm of a lever (Fig. 114). The stuffer is like a press, except that the food is forced out one hole. [Illustration: FIG. 114. Lard and fruit press.] CHAPTER XXIX MIXERS, BEATERS AND CHURNS; COFFEE POTS =207. Use of Mixers, Beaters and Churns.= Mixers, beaters and churns are all devices for agitating or stirring food. [Illustration: FIG. 115. Parts of bread mixer.] The simpler ones of these devices depend upon the motion of the hand (Fig. 115), while others have their velocity increased by means of cog wheels. The turning of the large wheel turns the small wheel as many times as number of cogs on the small wheel is contained in the number on the large wheel (see Fig. 116). To get even more speed or to apply the power at a different angle, a series of wheels are sometimes used. A few mixers, like the bread mixer, are simply machines which take the hands out of the food, thus tending to a higher degree of sanitation, and a change in the motion which may not be so tiring as kneading. They do not increase the speed of mixing.